Jane Tomlinson is determined to raise �1 million

The 40-year-old, from Leeds, is to take on the Half-Ironman UK Triathlon, one of the world's hardest sporting events.

The event in Dorset includes a 1.2-mile swim, a 56-mile bike ride and 13.1-mile run.

Mrs Tomlinson finished in six hours and 28 minutes last year, but her breast cancer is now in a more advanced stage and chemotherapy has damaged her heart.

Earlier this month she completed the London Triathlon for the third time and the Salford Triathlon alongside her daughters Suzanne, 19, and Rebecca, 16.

Epic bike ride

This is despite her epic 36-day bike ride from Rome to Leeds which she finished on 7 June vowing she would not do any more challenges.

Her husband Mike, 43, said the support they had received from thousands of people had encouraged her to carry on.

"This is our last big push to get to �1 million.

"She will pack in at some stage this autumn, then we don't know what will happen. It really depends on Jane," he said.

Mrs Tomlinson has already raised �850,000 for charity.