Bouncing bomb that flew in the face of reason

It'll never work, they said: but in Derbyshire you can see where the Dambusters legend first took flight

"This is tripe of the wildest description, there are so many 'ifs' and 'ands', there is not the smallest chance of it working." On 14 February 1943, that was the response of Air Chief Marshall Sir Arthur Harris when told of plans for a "bouncing bomb" to destroy dams in Germany. As Commander in Chief of Bomber Command, his views carried weight. But, thanks to the training missions that took place over the following three months, "Bomber" Harris was proved spectacularly wrong. Sixty years on, you can still sense the excitement of the Dambusters project on a walk around the reservoirs where they rehearsed.

"This is tripe of the wildest description, there are so many 'ifs' and 'ands', there is not the smallest chance of it working." On 14 February 1943, that was the response of Air Chief Marshall Sir Arthur Harris when told of plans for a "bouncing bomb" to destroy dams in Germany. As Commander in Chief of Bomber Command, his views carried weight. But, thanks to the training missions that took place over the following three months, "Bomber" Harris was proved spectacularly wrong. Sixty years on, you can still sense the excitement of the Dambusters project on a walk around the reservoirs where they rehearsed.

We were at the Upper Derwent Valley in Derbyshire for a guided six-mile walk to remember the extraordinary mission flown by 617 Squadron, who would become known as the Dambusters. We parked the car by the reservoir and followed the footpath around a corner.

The Derwent Dam, gothic and grey, confronted us. Water levels were high and the dam was full to overflowing – the escaping water thundered over the edge.

A Union flag flies over the dam's west tower. Sixty years ago, skilled young pilots from 617 Squadron flew over the dam too – only they didn't fly as high. Led by Squadron Leader Guy Gibson, they had come to practise the skills they would need for their top-secret mission. This was to be be no ordinary raid. Their intention was to destroy the Möhne, Sorpe and Eder dams, flooding the industrial Ruhr Valley in Germany. The theory was that steel production in the region would be devastated, crippling the country's war effort.

First, though, the pilots had to be trained to drop their oil-barrel-like bombs to maximum effect. And with simulators in short supply, the only solution was to practise on some of our own reservoirs. Derwent Dam, set in a steep-sided valley, was chosen for its similarity to the Möhne.

Barnes Wallis, an aircraft designer and engineer, had been asked to investigate targets that would cause maximum disruption to the German war effort. He concluded that dams comprised the most feasible target, but the RAF's existing munitions could not wreak the necessary damage. So he devised the "bouncing bomb". In the spring of 1943, 617 Squadron rehearsed up and down the valley, dropping flour bags instead of bombs. Locals complained of joyriding airmen. Roof tiles were lost and the wildlife bewildered. But 60 years on, the training missions have become the subject of an intriguing guided tour.

The walk is entitled Dambusters and Dambuilders. It is led by a park ranger, Dave Ashton, and begins at the Fairholme car park.

Take a picnic: the lunch stop is at Birchinlee, the site of a temporary town built to house the people who built the Derwent Dam and its nearby twin, the Howden Dam. Tin Town, as it became known, was founded in 1902 to house the navvies and their families who had come to work in the remote valley. It was a self-contained community, built from corrugated iron; it had a school, shops, a recreation hall, a pub, a bathhouse and a police station.

Once the dams were completed in 1916, the village was dismantled and the tight, yet temporary, community was scattered. Little remains except indentations in the ground, a few foundations and fascinating stories.

The walk finishes at the west tower of the Derwent Dam, where there is a small museum devoted to the Dambusters and Dambuilders. The exhibits are the collection of Vic Hallam, a Dambusters expert. Here the men and the event are remembered. Of the 19 aircraft that took off, only 11 returned and, to Barnes Wallis's deep distress, 53 men were lost. The squadron brought together the most experienced pilots. Proudly displayed under the flags of Great Britain, Australia, Canada, New Zealand and the United States are the uniforms of some of the airmen.

On display are copies of letters written by Guy Gibson to the mother of a lost airman, summing up the courage and sacrifice of the times. In the corner a video plays and The Dam Busters March, the theme music of the 1954 film, fills the museum. Parts of the film were made here, and the actor Richard Todd, who played Gibson, is a frequent visitor to the valley. Black-and-white photographs of the young airmen put faces to the legend, and the pictures of the breached dams in Germany are sobering.

From the museum, Dave, our guide, led us down into a tunnel, three feet wide and 1,110 feet long, that runs inside the dam. For a moment I thought I heard singing, so clear it stopped me in my tracks. But it was just echoes, tricks played by the wind and the water.

The next Dambusters and Dambuilders walk is on 13 August and is free. It starts at Fairholme car park at 10.30am and lasts for six hours. The museum is open only on Sundays: admission is free