Watford and the Dam Busters Raid

Most people will know that the Dam Busters raid in 1943 happened over the Mohne, Eder and Sorpe Dams in the Ruhr Valley, heartland of Germany’s industrial power in World War 2 and beyond. Many people may also know that the bouncing bomb was tested off Chesil beach in Dorset, and that the disused Nant-y-Gro dam in mid-Wales was where the explosives for use in the raid were tested. What is less well-known is that the Building Research Establishment (BRE) in Garston, north Watford, played a crucial role in turning the bouncing bomb from simply a theory into practical reality.

From experimenting with marbles in his garden, scientist Barnes Wallis had come up with an idea to “bounce” bombs over the anti-torpedo nets protecting German battleships and dams. Convincing sceptical Air Ministry officials was far from easy and so in 1940 Wallis approached Dr Norman Davey at the Building Research Station (now BRE) in Garston for help. Using German plans for the Mohne dam published in 1913, Davey designed a 1/50 scale model measuring 42 feet long and 3 feet high, which was then constructed in great secrecy in the grounds of the Research Station. Technicians cast 2 million scaled-down mortar blocks, which were painstakingly assembled across a stream in the Station grounds over a seven week period. Tests with miniature explosive charges indicated that it would require a 6000lb bomb, detonated against the wall 30 feet down when the reservoir was full, to successfully break through the dam.

The raid, now with the official title of Operation Chastise, was further refined and developed until 19 specially adapted Lancaster bombers from 617 Squadron left RAF Scampton to carry out the bombing mission on 16-17th May, 1943. A total of 53 out of the 133 aircrew on the raid were killed, a figure which caused great distress to Barnes Wallis. Apart from some disruption to the hydro-electric power provided by the dams, the physical damage brought about by Operation Chastise was relatively minor. The raid was, however, a great propaganda success and morale-booster for the British public, as well as proving the usefulness of so-called “earthquake bombs” in targeting heavily reinforced enemy installations.

After the initial trials in the winter of 1941, the model of the Mohne dam at the BRE was soon forgotten about and quickly became overgrown. It was only in 1997, when the BRE site was ear-marked for possible re-development, that the connection to the Dam Busters raid caught the public’s imagination. The model was subsequently declared a “scheduled monument” due to its national importance, so guaranteeing its survival for future generations. It is possible to see the model of the Mohne dam for yourself at certain times of the year, with details on the BRE’s website (. Or if you want to experience British imagination, technical expertise and bravery at its best, you could always watch out for one of the regular TV re-runs of the 1955 feature film of the mission, The Dam Busters – one of the classic British war movies of all time.)

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Operation Chastise, or the Dambusters’ Raid as it is better known, was one of the great technical achievements of the Second World War.

This article is part of our Celebrating St Albans History series. You can view all our historical facts on our Celebrating St Albans History page. If you have a historical fact you would like to add please let us know by using the contact form below or by emailing info@brethertonlaw.co.uk