The head of Bradford's world-renowned cancer research unit is to retire after a lifetime's work to combat the disease.

Professor John Double is leaving his post on March 31, after almost 25 years in Bradford.

The 60-year-old headed the unit at Bradford University as it became an internationally recognised centre of excellence.

Professor Barry Winn, dean of life sciences at the University, said Professor Double had been the driving force behind much of the progress.

"His value has been immense. It will be difficult to replace him. He is of the highest calibre and will be greatly missed by the University.

"Professor Double is valued by students and staff as someone who has been at the forefront of research development and trying to get improvements in patient care.

Prof Double began his career in cancer research when he spent 12 months on a sandwich course at the Institute of Cancer Research in London.

He returned there to study for a PhD with leading cancer expert, the late Tom Connors.

"He was such an inspirational character and he was so enthusiastic about his work," Prof Double said.

After obtaining his PhD, he worked at St Mary's Hospital Medical School in London in 1969, before moving to the University of Leeds Medical School.

After six years, he moved to Bradford in 1978 to work with the late Professor Robert Turner, supported by the then Yorkshire Cancer Research Campaign.

Prof Turner had begun chemotherapy work in Bradford in the 1950s and Professor Double said he was thrilled by his dream of providing individual therapy for patients.

"It was clear that a good deal of research would be necessary to help him realise this vision," he said.

Prof Double said cash was vital and the research was only possible thanks to fundraising by Bradford businessman Arnold Moore, who set up firstly the Whyte-Watson Turner Trust, then the charity War on Cancer.

Prof Double said at first they struggled with a lack of facilities but eventually moved into the Clinical Oncology Department and after an investment by Yorkshire Cancer Research, the charity's Laboratory of Drug Design was built next to it.

In 1999, War on Cancer agreed on a five-year investment plan for the unit.

The charity also merged with the Cancer Research Campaign, which agreed to honour War on Cancer's programme and to enhance it.

Bradford University matched this funding and invested £750,000.

The unit was renamed the Cancer Research Unit and now houses some of the best research facilities in the country.

Last year the two centres were given the umbrella title of the Tom Connors Cancer Research Centre, in honour of the pioneering expert.

Prof Double said the biggest change he had seen was scientists' better understanding of the molecular processes of cancer development.

"That's going to have a big impact in terms of developing new therapies."

Prof Double has also been involved in many other organisations, as well as being appointed Honorary Professor of Cancer Pharmacology at the University of Leeds.

Prof Double, who lives in Batley, will remain a section editor for the British Journal of Cancer until the end of the year.

He said he would be sad to leave but was looking forward to spending more time with his wife and family.

"My work has taken me away a great deal and I want to make up for lost time whilst I am still hopefully young and fit enough to do so."