Rod Newman will walk the whole way in a straitjacket while other colleagues from the Magic Circle juggle and perform tricks for passers-by.

If they reach their fundraising target, the 49-year-old has pledged to free himself from a straitjacket while tied inside a mailbag underwater, reminiscent of the feats performed by the legendary Harry Houdini, inset, last century.

Mr Newman, from Alverstoke, Gosport, said: 'I am doing rehearsals for the escape already, and I have tried a few runs in the swimming pool.

'I have done the escape from either the jacket or the bag, but never successfully done both together before.

'At the moment I have been practising it with a small oxygen canister, but when I do it for real I won't have any safety device, although I will have to have a safety diver down there with me.'

The former navy rescue diver has tried this dangerous stunt before – and it left him trapped and close to drowning.

'Last time I tried it for real I dislocated my shoulder underwater,' he added. 'It was a freak accident. I could not do anything, and for a moment I thought I was in real trouble.

'Thankfully my safety diver realised what was happening and brought me back to the surface.

'But I love challenges – if someone tells me something can't be done, maybe it can't be done by them – and that's my outlook on life.'

The 100-mile trek, organised by children's entertainer Sean Lobban, will be raising money for the leukaemia charity, the Anthony Nolan Trust.

Also taking part are Robert Bone, Laurie Brokenshire, Ian Marriott, Glen Stone, Harold Straker, Laura Tasker, and Jason Waskett.

It will start in Cosham on May 5, take in Southampton, Winchester, Basingstoke, and Reading before finishing at the Magic Circle's HQ in London on May 10.