The consequences of new NHS funding proposals will be “severe” for people fighting illnesses including cancer and heart disease and could result in “avoidable deaths”, according to a senior Birmingham consultant.

A total of 345 doctors have signed an open letter to NHS chief executive Simon Stevens, describing the proposals, which would see only half of the funding for extra cases treated at specialist hospitals covered, as “destructive”.

The letter maintains that hospitals will be forced to either not offer treatment to these extra patients, or cover the costs of treating them through cuts in other areas, including staffing levels, and warned waiting times will increase.

Lead author Dr David Rosser, medical director of University Hospitals Birmingham Foundation trust, said: “The clinical consequences of these longer waiting times and a lower quality service to patients with conditions such as heart disease, liver disease, leukaemia, complex cancers etc will be severe.

“There will inevitably be a significant number of patients suffering unnecessarily, for example by needing more extensive surgery due to their cancer progressing during the wait,” the letter adds.

The consultation on the proposals is due to end today.

A spokesman for NHS England said: “We will listen carefully to all consultation responses on these proposals, while recognising that providers of specialised services have enjoyed income increases of over £1 billion over the past two years and now have some of the highest profit margins in the NHS - all at a time when there is also a strong case for investment in ambulance services, mental health services, primary care and A&Es.”

In a separate letter, published in the Telegraph, a director of a leading cancer centre challenged the Government to “put its money where its mouth is” when it comes to cancer care.

Simon Oberst, director of clinical development at the Cambridge Cancer Centre, said: “While hospitals accept the need for further efficiency savings where possible, the people who are going to suffer are cancer patients.”