Parachute Mine Defused in London, October 1969

Having conducted some research in the Royal Engineer Bomb Disposal (BD) archives at Carver Barracks, I came across a fascinating report covering the neutralising of a WW2 German Type GC parachute mine at Burghley Road, London, by Major G.R. Fletcher MBE, Royal Engineers. When I started to read the report I was transfixed, it was an impossible situation with so much to lose. It was a situation that every BD Officer must have dreaded, but the way Maj. Fletcher (obituary b.1924, d.2010), already an MBE, dealt with the incident ultimately led to him being awarded the George Medal. I thought it would be appropriate to share the full incident report, written by Maj. Fletcher himself. It is also interesting to note that WOII S. Hambrook (obituary b.1933, d.2015) was also awarded a George Medal for his conduct in defusing this mine, and was later awarded an MBE for his military service. This incident featured in both mens obituaries and the original report below reads as a tale of peace time heroism and bravery.

REPORT OF THE GC PARACHUTE MINE INCIDENT AT BURGHLEY ROAD, LONDON BY MAJOR G.R. FLETCHER MBE RE

At 1200 hrs on Wednesday 1 Oct 69 a UXB (Unexploded Bomb) report was received by the BD (Bomb Disposal) Operations Room and passed to myself. The report came from the Kentish Town Police, the message read:

20″ dia object revealed in the side of a deep trench, colour Black and thought to be a bomb of sorts. Location a building site at Burghley Road, Camden.

The report originated from a Sgt. DUFFIELD of the Kentish Town Police.

The area in North London was heavily bombed during the War. The above map was compiled at the time and each dot represents a bomb that fell. The full interactive map can be found at Bomb Sight, the National Archives dedicated website.

I immediately contacted the police to get precise details. Many false alarms are received the unit, by careful checking detail one can usually discover if there is a reasonable chance of the object being a bomb or similar. After talking to the police sergeant, I soon formed the  opinion that without doubt there was a large bomb.

After a very quick cup of tea and a sandwich

WOII HAMBROOK also asked if he could come, to this I agreed. I requested a police escort, this was duly arranged and an RV (rendezvous) fixed for 1315 hrs at a pub called “The Dover Patrol.” After a very quick cup of tea and a sandwich, the Team and myself in a Morris Minor traveller and WOII Hambrook driving a Landrover, left Headquarters at 1230. We arrived at the RV at 1300 hrs. At 1315 the police escort arrived and we were on our way at once. The pace and progress through London was rapid and dramatic. Police sirens sounding continuously and blue lamps flashing, bells ringing. At 1345 arrive on site and was shown the object.

Looked down into the excavation, it must have been 10-12 ft deep as the report had said. We could just see a spherical object sticking out from the side of the trench, it was black with showing underneath traces of green yellow aluminium priming paint. I clambered down into the trench and soon formed the opinion that here we had a rare and very dangerous bird indeed.

A rare and very dangerous bird indeed

Non-Contact, Parachute Ground (Land) Mine Type GC (MUN 3509) Second World War period German land and sea mine. Copyright: (c) IWM.
Original Source: http://www.iwm.org.uk/collections/item/object/30020471

The casing was soon established as being aluminium alloy and the general appearance left me in no doubt that here was a parachute mine of one type or another, presumably fitted with a combination of any of the following detonating devices:

  • Magnetic unit
  • Acoustic unit
  • Timing unit with eighty day clock
  • 34 bomb type clockwork fuze
  • PSE with a Photo Electric Cell, small charge in the tail unit, ZUS 40 to prevent fuze removal
  • Counting device to allow a number of impulses before detonating

I immediately put into operation the following – Ordered up the full disposal equipment, stopped all unnecessary movement on the site, and arranged to clear the site of workmen, informed the police superintendent of the nature of the hazard and gave them instructions regarding safety precautions I required him to take. This done and with the aid of WOII Hambrook and helped by Lcpl HARKNESS and Sapper GARRIGAN, we carefully set to work to uncover more of the mine, to establish its exact identity.

After about half an hours very careful work the nose of the mine was uncovered revealing a filling plate, this was a great piece of fortune for it established at once the device as a ‘G’ C mine. It was now fairly certain what we were against. I estimated that the mine would be fitted with the following devices or a combination of them:

  • Type 34 clockwork bomb fuse
  • Magnetic-acoustic unit
  • 6 to 80 day clockwork timing unit
  • ZUS 40 to prevent fuze withdrawal and possibly a PSEs in one form or another 

Judging from the condition of the paint and the condition of the allow the mine appeared to be in absolutely mint condition. The four screws that held the filling plate in position were good, and with luck would come out allowing the plate to be removed. I also noticed a certain amount of liquid owing out of the joint between the main body and plate.

Up until this time it had not been possible to prepare a positive plan of action. I was now armed with sufficient information to weigh all factors and settle on a straight run of disposal sequence with an optimum of success.

The factors to consider were as follows:

The Site and Location

The immediate are was a very restricted building sits in the heart of London with 20 yards or so in all directions, of clear space to the first partly constructed buildings.

To the north and 30 yards away was an underground railway. 50 yards and running parallel to this underground railway was a surface railway, both, I was told, were vital communications, one of them carried rush hour commuter traffic to Southend. Beyond both railways and facing the site were three high blocks of flats, well within 150 yards radius. In other directions and within the 150 yds radius were rows of old terraced houses. Bounding the site on two sides were busy main roads.

OS 6-inch map, England and Wales, London Sheet H. Revised 1938, Published ca. 1946 showing Burghley Road in the centre of a busy built up area during the war when the bomb dropped.

The Mine

The mine was embedded 10-12 ft deep in very hard London clay with the previously mentioned detonating devices all of which could be alive and (unreadable). The 34 fuze was certain to be poised in position ready to start unwinding and strike. There was also the distinct possibility of the acoustic device being sensitive to noise and the magnetic device being able to react to metal tools.

Safety

Civilians: No problem here, complete evacuation was ordered, however it would be difficult to enforce over too long a period.

The BD crew: In peace time this is a very important factor.

Courses of Action

Two courses fo action clearly presented themselves:

a. Dig down, move the mine to get al all the systems. Render these safe and steam out, blow the fuze pockets.

b. Leave the mine embedded and stable in the clay, remove the filling plate and steam out and blow the fuze pockets.

Course a.

The excavation would take 24-30 hrs of very, very careful digging with the possibility of timbering. The whole crew including NCOs and Sappers would work over the mine for a considerable period putting them all at risk. Having uncovered the mine no doubt it would have to be moved and disturbed to get at the fuze and other detonating devices. The 34 fuze could not have been removed because of the possible ZUS 40. Irrespective of rendering safe the various detonating devices I would eventually have steamed out the explosive rather than moved the filled mine through the heart of London. This course could have taken 24-30 hrs plus steaming out time of 10 hrs and would have prolonged:

  • The danger time
  • The evacuation time
  • The closure of two rail routes with no less risk of explosion and consequent damage to buildings and communications
  • Put a lot of people at risk

Course b.

Would involve removing the nose filling plate and steaming out the explosive with the fuze system intact, with the realisation that the extreme changes of temperature might cause movement in the clockwork fuze and allow it to unwind and ‘strike.’ For speculation was the unknown reactions to extreme heat on the Hexamite filling and this filling’s chemical reaction on an aluminium case. Due thought had to be given to heat on a number of detonators and gaines that may have crystallised with age. But of prime importance this course would involve the exposure to risk of the minimum number of people, myself, WOII Hambrook and, as required, St. Bromley. This number of people would be required for the sheer physical effort required to steam out, move hoses, bail out water and remove explosive from the excavation. Further, the operation could be completed in about 10 hrs as opposed to 30-40 hrs. Also as time advanced and steaming out progressed the chances of damage would recede as the explosive filling became less and less. I judged the possibility of accidental detonation by the firing devices to be similar no matter which course was adopted. The advantages of course b., steam out at once with maximum precautions were considerable so I decided to adopt it. 

1530 hrs – Held a conference with the police, civil defence authority and railway authority at which I outlined my plans, gave my requirements for evacuation and rail closures, provision to allow families to make the return home from work, children to return home from school, to allow the civil defence to make their own arrangements to receiving these families at their centres, and to allow the worst of the evening rush hour traffic on the rail and road to subside. I agreed to a deadline of 1830 hrs for the complete evacuation and the start of the operation.

1545 hrs – Continued to prepare the mine for steaming out. Fully exposed the filling plate. Three of the retaining screws in the cover plate came out easily but the combined efforts of WOII Hambrook and myself resulted in a partly sheared head of the remaining screw. The only solution was to drill it out. This was done and the plate eased off revealing very hard cast hexameter oozing a small amount of liquid. 

1630 hrs – All equipment on site and work put in hand to set up for steaming out. This work included the assembly of the lighting set, sandbagging, improvements to the stethoscope sentry position and so on, all proceeded rapidly and efficiently and by 1700 hrs all was ready for the operation to start.

1700 hrs – Tea and buns.

1800 hrs – All possible precautions completed and final conference with the police, civil defence and British railways. Also the first of many on site press conferences. 

1815 hrs – Generators started, steam up for testing, lighting set tested, all is now ready.

1825 hrs – A his descends over the site. Traffic stops in the street nearby. The railway is completely silent, in the heart of London empty houses and flats surround us on all sides. It is quite eerie.

1830 hrs – Generators belch smoke and flame and starts the long, long night.

1900 hrs – I inspect the mine, am alarmed and disappointed at the progress of the steaming out. Hexamite is tremendously hard and hardly any impression in this first half hour has been made on the filling. The only way of speeding up the progress was to chip out a certain amount of the hexamite so that the steam nozzle has got a start and then cover with an extra layer of sandbags to contain the heat. This was done and soon steaming out was continuing.

2000 hrs – Further inspection, progress is very slow but certainly showing a sign of speeding up, nevertheless at this pace I calculated it was going to take us about 24 hrs of steaming to remove 1620 lbs of hexameter. At this time the second steam generator arrived, this being ordered forward in case of breakdown. To speed up progress it was immediately out into operation so there could be two steam hoses playing on the explosive at the same time.

2100 hrs – Pleased to see the progress very much improved. At this point I was able to calculate, given a reasonable amount of luck, steaming out should be completed ay around 0400 hrs the following morning. The whole crew had a short break for a well earned newspaper packet of fish and chips organised by WOII Hambrook. Steaming was now going at a pace both generators were working well and clouds of steam were issuing forth from the excavation. An inspection of the mine and the excavation revealed a certain amount of caving in of the trench caused by an excessive amount of water from the “steaming out” operation. This required some revetment which was soon completed. It was now also necessary to start removing the bulk of the explosive from the excavation as it was beginning to pile up and re-harden in the cold night air. This was put in hand, the explosive was dug out, put into sandbags and hauled to the surface. At this time another conference was called with the police, civil defence and railway officials to give them the latest estimation of completion time and to advise them that their evacuees should give up all thought of returning home that night and should bed down. I was now able to estimate that the operation should be completed and the fuze pocket blown at about 0600 hrs the following morning.

2200 hrs – Both steam generators going full blast, at this time another generator was ordered from HQ as reserve in case either one of the two in use broke down. When steaming out is imperative to keen the steam pressure high and going all the time full blast without stopping. I had also given a deadline and competition time for the operation and was most anxious to keep it. I dreaded the thought of having to delay the deadline and or to change the method of dealing with the incident. By now we were having to cope with a very keen and persistent public clambering for news. The only way to solve this situation was to have impromptu conferences between visits to the mine. This appeared to keep all quite happy and certainly prevented them from forcing themselves onto the site where they would have probably got in the way. By this time also the BBC and (unreadable) plus the big dailies were exerting real pressure for a story. I gave the latest details and advised them that the need for a further visit and conference would be at about 0400 hrs. They appeared quire happy at this and I think they all then went off to the evacuees in the school. (unreadable) they were a friendly and polite lot and happy to het any sort of news.

2300 hrs – At this stage all visits to the mine had to be kept to an absolute minimum. Two steam jets were now right inside the mine, the case and ancillary parts were getting extremely hot and the steam would soon be playing on the fuzing mechanism with the possibility of expanding the parts and allowing them to free and fire, the heat could also possibly have gingered up the batteries. There is positive evidence that batteries 20 years old which had been in mine laid up at sea have still had sufficient life in them to fire five detonators, so there was no question in our minds that the batteries might not be live, as far as we were concerned they were live. At this point, all personnel not required to go near the bomb were given strict instructions to remain under cover. Some additional personnel had to expose themselves to danger from time to time i.i. the NCO, Lcpl WISEMAN, in charge of the steam generators, Spr NICHOLAS who was in charge of the generator supplying electricity for the flood-lighting and of course the people actually involved feeding the hose lines into the bomb.

0020 hrs – Third steam generator arrived, this was just as well as the second steam generator was just about to give up its last gasp. The erratic performance of the second steam generator had caused alternative heating and cooling of the steam nozzles, this in turn cause liquid explosive to be gradually sucked up into the pipes causing them to be blocked. The only way to free the pipes was to remove them from the mine and bash them on the ground and allow the steam pressure to blow the bits of explosive out. WOII Hambrook and Sgt Bramley became very adept at this procedure over the night.

We kept our fingers crossed in the hope that the heat would not free the clock-work fuze mechanism

0030 hrs – The team continues to be in excellent form and good spirit going their various tasks with spirit and energy. Generator men attending the reluctant steam generators, Spr Nicholas tending his lighting set generator, Mr. Swinney organising his lorries and drivers and some of the sappers filling sandbags to damp down the explosion that would occur at 0600 hrs when we blew the fuze pocket and for revetting. The explosive was now oozing out of the mine case thick and fast, we kept our fingers crossed in the hope that the heat would not free the clock-work fuze mechanism and ponder on the effects the cold water will have, on the fuze when we flood the case before we place the demolition charge inside. Will the contracting and expanding parts pf the mechanism now be free and cause the striker to move. Will the detonator cap be more sensitive. These things we cannot be sure about. Thoughts rush to ones mind as one lays in the bottom of the trench peering into the inside of the mine, through the steam and throat catching fumes of the melting explosive or while testing the depth of the explosive with a problem or putting ones eye to the filling plate hole to see exactly what progress is being made to the explosive inside the case.

0200 hrs – A very welcome break. The civil defence of Camden Town are really on the ball. They kindly arranged a very welcome meal of soup, bangers, bread rolls and tea. This was most welcome and was our first real meal since breakfast. They had also promised us a big breakfast when we finished in the morning.

0230 hrs – Attended the mine with WOII Hambrook and with Sgt Bromley bailing out the excavation to enable us to get near the case. At the moment when we were bending over the mine adjusting the hoses and observing progress there was a large “woof” and a tremendous sheet of flame for a split second seemed that the explosive had partially detonated. On getting out of the hole rather quickly horrified to see our new steam generator on fire plus a couple of jerry cans blazing away merrily. Disaster appeared to be upon us, if we lost this generator we would be put back hours and hours. No 1 generator, the one that came out with the crash crew, was already beginning to flag. After seconds of stunned amazement, everyone in the vicinity sprang into action. A nearby vehicle was driven out of danger, three fire extinguishers were brought into action, petrol cans were kicked away and the fire put out in rapid time. Thanks to the action of Mr. STOAKES, who drove the vehicle, Mr. SWINNEY, Cpl BOLDOCK and Spr THOMAS.

After 15 minutes Cpl Boldock had cleaned up the equipment, sorted out the steam generator and got it going again. This stoppage had allowed the steam generator and the steam pipes to cool off and re-started the trouble of blocked pipes. This trouble would plague us for the rest of the operation, for once the pipes get really blocked it is very, very hard during a continuous operation to clean them out. Nevertheless we were thankful that we got away with this fire so lightly.

0230 hrs – The routine progresses. Continuous steam as hot and as at high a pressure as we could get it, feeding the hoses into the mine, dig out the explosive, bail out the water, shore up the trench. The sheer physical effort requires that three people must work on the task together.

At that moment from the direction of the site there came a loud bang and a sheet of flame

0400 hrs – A message from the police. Press, radio and TV are getting impatient and would like further information. Impromptu press conference. Met all the press outside the police barrier and judged the best way to keep them happy was to let them visit the site. So after warning them that they approach the mine completely at their own risk, I suggested that they might do this. They all seemed very pleased, their editors wrath no doubt being greater than the fear of possible detonation. At that moment from the direction of the site there came a loud bang and a sheet of flame, and once again, I am by myself. Doorways, lamp-posts, cars sheltering surprised members of the press. One of our generators has again been playing up and the flame had gone out, re-ignition with excess fuel had caused this bang and tremendous flash. Reassured they trooped after up on the site where I gave them ten minutes of fairly concentrated freedom to film, interview, and talk with all and sundry. At 0430 hrs they all appeared to be  happy and disappeared to their respective cars and their respective “slave driving” editors, to meet their deadlines.

The Daily Mirror front page from 2 October 1969, with thanks to Trinity Mirror, Digitised by Findmypast Newspaper Archive Limited.

0500 hrs – Inspected the inside of the mine and found it to be 80% clear of explosive. However there remained a large piece of explosive about three (times) the size of a football which appeared to be extra hard. It was too large to leave, there must have been 40 or 50 lbs worth. There was also a quantity still left in the bottom half of the mine. To allow the explosive in the bottom half of the mine to drain out, a number of holes were drilled in the mine case in the lower half of the nose. Although the holes were not large I judged them sufficient to allow the explosive to ooze out when it was sufficiently hot. The generators were restarted, but despite the great efforts by Cpl Block and Lcpl Wiseman the generators were now flagging and at their last gasp. I decided to continue with the steaming as the explosive content was still too great to allow detonation of the fuze pockets. At the rate of progress I judged that steaming out would take another two hours. I decided that we would have another hours steaming and then the operation just would have to stop to achieve the reasonable deadline of blowing the fuze pocket at 0700 hrs. Called an on site conference with the police, civil defence and British Railways officials and informed them that the fuze pocket would be blown at 0700 hrs and I asked the police to inform all the local inhabitants of houses within a radius of 600 yds to open their windows. I also told the police that the bomb case was now virtually empty and it would be safe for the evacuees to return to their homes beginning 0600 hrs.

The Daily Mirror rear page from 2 October 1969, with thanks to Trinity Mirror, Digitised by Findmypast Newspaper Archive Limited.

0600 hrs – Carried out a final inspection of the mine case and (established) that it was virtually clear of explosives and certainly in a satisfactory condition to blow the fuze pockets. All hands were put to mitigating the (unreadable) above the mine and the trench. The preparations were made to the fuze pockets. A charge of ½ lb was prepared and lowered at the end of a 5 ft long stick. Long enough to protrude 2 ft out of the mine case. The means of initiation was one primer, detonator and 3 ft safety fuze.

0645 hrs – The charge was placed astride the (unreadable) fuze pocket, (unreadable) up the stick securely lashed in place to a picket outside the mine case. Further sandbagging proceeded to contain the explosive charge, which would amount at this stage to about 10 lbs of fuze pocket, ½ lb of demolition charge and possible 30 lbs of random explosive lodged in corners of the mine case. Prior to this the mine case was cooled off by flooding with cold water from the steam generators.

0650 hrs – All prepared. Police informed that we intend to blow at 0700 hrs. Police confirm that all local inhabitants have been informed and that as many windows have been opened as possible.

It was a bigger explosion than expected

0700 hrs – Warning whistle is blown. Fuzes lit and we walk away to take cover. The demolition charge is fitted with 1 ½ minutes worth of fuze. I check my watch, one minute to go, one minute 30 secs to go, still no bang. One minute 40 secs gone, no bang. One min 50 still no bang, one min 55 bang, off she goes to our great relief. Sandbags pass over our heads and crash and flop into the cold empty dusty partly constructed buildings surrounding us. It was a bigger explosion than expected, possibly there was a little more explosive hidden around the casing than one could see. This bigger explosion had helped us considerably. It had partly excavated the case and enabled us to remove the resultant scrap metal with very little digging. After checking the area for parts that might contain explosive, ordered the men to the civil defence rest centre where we were promised a large breakfast. I personally experienced at this point a great feeling of relief that all had gone well with no damage to the crew. The sequence of the operation had gone smoothly, small complications had been ironed out as we had gone along. The crew had worked well and willingly the whole night, used their initiative. I am quite confident in saying there could not have been a better team. WOII Hambrook and Sgt Bromley both deserve special credit for their skill and devotion to duty in their respective spheres. Both worked in arduous conditions and were fully exposed to real danger. The remainder of the team worked efficiently and with spirit. They were:

  • Lcply HARKNESS D (Helped expose the mine)
  • Spr J.D. GARRIGAN (Helped expose the mine)
  • Spr. J.C. BRIDGWATER (General duties)
  • Spr. J.L ROBERTS (General duties)
  • Spr J. THOMAS (Put out the steam generator fire)
  • Cpl W. BOLDOCK (Kept plant going)
  • Lcpl R.I. WISEMAN (Kept plant going)
  • Spr J. NICHOLAS (Kept plant going)
  • Mr. T. SWINNEY (Who organised transport)
  • Mr. R STOAKES (Who drove the vehicle away from the burning generator)
  • Mr. J. PIKE (Driver)

This incident was under constant surveillance by the Press, TV and Radio, one really did feel as if one were in the proverbial gold fish bowl, with the eyes of the country upon us and the reputation of our unit, and for that matter the Royal Engineers, at stake. No doubt our activities would also be keenly observed by other EOD (Explosive Ordnance Disposal) bodies. It would have been virtually impossible to cover up a mistake, a wrong decision, an excessive delay, or real shortcoming in our equipment or techniques. 

As far as records reveal this was the first parachute mine the army has dealt with since the last war, it is heartening to note that despite the “gap” our training and methods stood the strain and the operation was completed without a serious hitch.

Needless to say we received excellent backing from HQ BD, from the JSBDS who produced extra reference manuals, and from the helpful and lively person of CPO BRASSINGTON who was Orderly Officer that day.