Patients suffering from cancer affecting the head, neck and bowel are most likely to experience life-threatening waits for treatment, a Cancer Research UK study has found.

The charity claims that unacceptable delays are putting patients' lives at risk, suggesting that a four-week delay to surgery increases the risk of dying by 6-8 percent for many cancers.

NHS England aims to begin treatment for 85 percent of cancer patients within 62 days of an urgent referral but only meets this target in cases of Haematological and skin cancer.

Head, neck and bowel cancer sufferers experience the longest waits, with gynaecological and lung cancer patients also not receiving treatment within 62 days in nearly half of cases.

If this does not improve, 300,000 cancer patients in England won't start treatment on time over the next five years, according to the charity.

Health Secretary Wes Streeting, himself a cancer survivor, has vowed to ensure that cancer waiting time targets are met by the end of the current parliament, in light of a scathing report by Lord Darzi on the state of the NHS.

Cancer Research UK evidence and implementation director Naser Turabi said such long waits were unacceptable.

He said: "Cancer patients deserve to be treated on time regardless of their cancer type.

"The new government has a huge opportunity to turn things around and ensure cancer wait time targets are being met by the end of this parliament.

"But there are no quick fixes and long-term planning and reform is essential.

"A 10-year plan which provides the NHS with additional staff alongside key diagnostic equipment will bring down waiting lists and save lives."

Michelle Mitchell, CEO of Cancer Research said that she was encouraged by Mr Streeting's vow and promised to work with the government to drive down waiting times.

She said: "Our health service does not have the required resources to cope with record numbers of people being diagnosed with cancer.

"Unless action is taken, things could be even worse in five years' time."

Lord Darzi's report, published last week, warned the government that the National Health Service is in "serious trouble" and in need of rebuilding public trust damaged by several factors, not solely in the NHS' control.