Newly diagnosed cancer patients will be signed up for NHS fitness bootcamps, in a radical bid to boost survival.

Thousands will be enrolled in “prehab“ schemes in the new year, with patients asked to complete around three weeks’ intensive exercise, before treatment gets underway.

Experts say getting fighting fit can help the body tolerate gruelling regimes such as chemotherapy.

But the plan is likely to prove controversial, as patients will be asked to sign up for the gym within around 48 hours of being given a devastating diagnosis.

Simon Stevens, NHS chief executive, said the radical approach aimed to “prime” the body for recovery, boosting strength before chemotherapy or major surgery.

He told The Telegraph: “Cancer treatments now work better than ever, but they can really take a toll on your body. So there’s increasing evidence that it's really worth trying to get match fit ahead of chemo or major surgery.

“In effect you are 'priming' your own recovery before your treatment even begins - boosting strength and wellbeing, often meaning you can also come home from hospital sooner,” he said.

Over the next year, more than 4,000 cancer patients in Manchester, London, Hampshire, Yorkshire, and Leicester will be prescribed exercise regimes either at the point of diagnosis, or within days of receiving the news.