17 May 1943, 00.49 hrs: by this time three specially modified Lancasters had attacked the Möhne Dam with their unique Upkeep ‘bouncing bombs’. Commanding the operation, Guy Gibson had gone first, his Upkeep mine successfully detonating against the dam wall. ‘Hoppy’ Hopgood quickly followed but his aircraft, hit by flak had crashed; his Upkeep, released a second too late, bounced over the dam wall to explode on the power station below just as Mick Martin began the next attack. He, like Gibson, succeeded – their bombs throwing towering columns of water into the air. But despite their accuracy the dam wall held.

Time was ticking by as Gibson called on Dinghy Young to make the next attack. In Perfect Timing, a drawing of outstanding drama, Richard Taylor graphically depicts the moments that followed. Against the fiery backdrop of Hopgood’s near miss Gibson, flying to Young’s starboard side is joined by Mick Martin to port as they attempt to draw some of the enemy flak away from Young as he releases his own Upkeep. With perfect timing the mine bounces over the water and within seconds it too will detonate against the dam wall. Fatally weakened, it will take just one further strike, this time by David Maltby, to deliver the final coup- de-grâce. The first of Germany’s great dams had finally been breached, another – the Eder – will shortly follow.