WHEN Michael Berry was told his cancer was no longer in control, son Tim decided they needed an all-consuming mission.

Chairman of English Lakes Hotels, Michael had long been captivated by the massive flying boats he had first seen as a child with his father in Cornwall.

He was 14 in 1944, fishing on an eerily empty Windermere, one warm summer's day. Not a sail to be seen, or whisper of noise to be heard, the stillness was shattered by a roar of four massive 1,000hp engines, as the 112ft wide, 85ft long monster aimed straight for him.

"It was frightening. I did a 90-degree turn and headed to the side of the water."

By the time Tim opened the Low Wood Waters Sports Centre in l987, only memories and myths remained of Short Brothers' mighty enterprise, employing 1,500 people at White Cross Bay.

He set up a diving school and started trawling the lake bed for wrecks.

"Increasingly, I was hearing stories that there were two or three Short Sunderlands down there," he explained.

"Tales had been going around since the war that there was too much military stuff still around and orders were given to pull the plugs and sink them.

"It made sense. All around the British Isles, a lot of equipment was being dumped. Expensive to dispose of, scuttling the Sunderlands would have been logical."

Encouraged by early finds of packing cases full of engineering tools in shallow waters around White Cross Bay, Tim stumbled on a Sunderland wheel.

"It was over six feet across. Apparently, locals had used them for moorings. But for me, it said searching further made sense."

Buying basic sonar equipment, Tim kept operations low-key and sporadic.

Father and son heard from a friend how at a reunion dinner an ex-RAF man talked of how Sunderlands had been ditched here.

The pace only began to quicken this year, when Michael was told by Manchester cancer hospital Christie's that his condition was "no longer OK".

"I wanted a project we could work on together. Solving the Sunderlands mystery once and for all seemed like a good solution," explained Tim.

Ironically, the BBC contacted the pair soon afterwards. It was making an Inside Out programme and wanted to prove by the end of September whether or not there were flying boats on the bed of Windermere.

By this time, the two had been joined by Marcus Cardew, managing director of Systems Technologies Limited, in Ulverston, leaders in subsonic equipment, who brought specialist knowledge to the project.

Using sophisticated side-scan apparatus, they were able to carry out detailed surveillance. Much of the scuppering speculation centred on High Wray Bay, which has some of the lake's deepest waters, only 100 yards from the shoreline.

The BBC came up with a diver, who said he had found two submerged Smart Sunderlands in Windermere 20 years earlier, giving fairly precise locations. He has since been discredited, but the false leads severely hampered progress.

Although some flying boat breeds have survived, there are no Short Sunderlands left anywhere in the world, says Tim.

Working through grid references, occasionally with a film crew tagging along, the team spent the summer searching in a £10,000 boat Michael bought specially for the mission.

Veiled in secrecy, at the request of the BBC, fervent activity was taking place on and off the lake.

A burgeoning file documents the progress. Michael left no stone unturned in a bid to keep matters above board. Letters to and from the Royal Air Force, Ministry of Defence, and House of Commons are carefully filed.

"If there was a Sunderland down there I wanted it brought up and displayed properly in memory of Coastal Command," said Michael.

"It would have involved a six figure sum. We would have financed it initially ourselves, backed by charitable organisations.

"There would have been a great deal of interest and we had everything in motion. Solicitors in Manchester were working on getting charitable status."

Plans had even been made to recover the massive hulk, with an unladen weight of 17-and-a-half tons.

But by the end of September, England's longest lake had still not revealed any of her secrets, despite state-of-the-art sonar gear.

"I had been full of expectations and expected instant discovery," confessed Michael.

"No one had seen any of the flying boats take off after the war, so what happened to the two or three which were left?"

He was beginning to convince himself the whole thing was a myth after all, when he received a letter this month from an ex-RAF man, who had seen BBC's Inside Out programme.

He says he was responsible for bringing a Sunderland to Windermere, on July 26, 1944 - to be scrapped.

Tim is carrying on, concentrating efforts around the deep water contours of High Wray Bay.

Whatever the outcome, father and son have had precious quality time.

"Cancer so focuses the mind on how much time you have left together," said Tim.

"Finding a Sunderland would have been a bonus."

Silvercrest Submarines ran a tourist vessel in the lake for a couple of seasons, after clinching planning permission in 1997. Despite high hopes of coming across the odd Sunderland, Winder-mere's murky bed revealed nothing but atrocious visibility.