A memorial to the engineer who invented the bouncing bomb used in the infamous Dambusters raids during the Second World War has been unveiled in Harmondsworth.

A blue plaque commemorating Sir Barnes Wallis is in place in Moor Lane – on a site where his water-skipping explosives were tested on models at the Road Research Laboratories.

More than 100 people attended the unveiling ceremony on Thursday last week, the day after Sir Barnes’s birthday.

Guests included war veterans, former colleagues of the scientist and serving RAF personnel.

Children from the nearby Harmondsworth Primary School gave the proceedings a very British feel by waving union flags.

Sir Barnes’s daughter, Mary Stopes-Roe, and his grandson, Jonathan Stopes-Roe, were guests of honour.

The memorial plaque reads that Sir Barnes Neville Wallis was ‘Designer of R100 airship, geodetic construction, Upkeep, Highball, Tallboy and Grand Slam bombs. Pioneer of swing-wing and tailless aircraft and hypersonic flight’.

The Derby-born engineer made breakthroughs in aircraft design before the onset of the war, during which he turned his attention to devising large bombs that would aid the Allies’ strategy for defeating Nazi Germany.

He experimented with explosive devices that skipped over water and sank next to their targets. The barrel-shaped bombs, which were to be dropped at a given speed and height with backspin to give them momentum and leap across the water surface, initially disappointed in trials.

Undeterred, Sir Barnes made adjustments to the design and the bouncing bombs worked.

This type of attack was deployed for the first time to good effect by 617 Squadron RAF during Operation Chastise on May 16 and 17, 1943, when Lancaster bombers destroyed the Mohne and Eder dams in the Ruhr region of west Germany.

The raids led to massive flooding, which disrupted the German coal and steel industries, were immortalised in the 1955 film, Dam Busters.

Sir Barnes, who was knighted in 1968, died in 1979 at the age of 92 in Effingham, Surrey.