A group of cancer experts have challenged political parties to explain how they would cut waits for diagnosis and treatment of the disease, which they said offered the greatest hope of saving lives and improving life expectancy.

In a joint letter, the five experts - including three university professors and a representative of the Teenage Cancer Trust - said they wanted to focus the health debate ahead of the May 6 general election on “how to deliver early detection and rapid treatment”.

The experts did not express an allegiance to any political party, but their letter was distributed to the press by Labour.

And their argument boosts Labour’s argument for a legally-enforceable guarantee of cancer test results within one week of referral - something which Conservatives have not matched.

The Tories have instead highlighted their promise to spend £200 million to give patients access to cancer drugs which have been licensed but have not received approval from the health spending watchdog NICE.

Today’s letter was signed by Ian Ellis, Professor of Cancer Pathology at the University of Nottingham; Hilary Thomas, Honorary Professor of Oncology at the University of Surrey; Professor Mike Kirby, of the University of Hertfordshire and The Prostate Centre; Michelle Saxby, of the Teenage Cancer Trust; and Essex GP Dr Shaun Firth.

They wrote: “Improvements in how quickly we are able to diagnose and begin to treat cancers offer the greatest potential for saving lives and improving the life expectancy of those affected by cancer.

“That’s why we challenge each of the three parties to explain how they will ensure that waits for tests become a thing of the past and that patients diagnosed with cancer can begin treatment with the shortest possible delay.

“By focusing the debate on how to deliver early detection and rapid treatment, we can test each party’s plans for helping the NHS grapple with a disease that will affect so many of us.”