Dorchester blood donors are helping a national study into deadly diseases.

A research team from the Department of Clinical Pharmacology of Oxford University is at St Peter's Church Hall, Dorchester, today for a second day.

Experts are asking those whose grandparents live in the same area to donate small samples of blood for a project called People of the British Isles.

Information from across the UK will be used to produce a genetic map of the country and look for links to diseases such as cancer and heart disease.

Professor Sir Walter Bodmer, project leader, said the event was going well.

He said: "We are collecting blood samples as a source of DNA, and DNA carries the blueprint of life.

"Using this we can say something about people's origins and the structure of the British population. We are aiming for 3,500 samples throughout the UK and Dorchester is an interesting place from that point of view."

Visitors to the hall filled in questionnaires and gave anonymous samples of blood.

Tourist Barbara Cowell said she was delighted to help the project. She was visiting Dorchester when she offered to take part yesterday.

She said: "I think this study is wonderful and exactly the sort of thing we should be doing.

"I didn't realise I would be coming here today but it is no big deal - I am used to giving blood. This is a hugely important thing to be doing."

Last night historian Julian Richards, who has appeared in the BBC's Meet the Ancestors programme, hosted a reception at the hall.

He introduced project leader Professor Sir Walter Bodmer, who talked to visitors about his research.

The five-year study, funded by the Wellcome Trust, will see samples collected from all over the UK.

University staff are in South Street again today from 9am to 2pm and are appealing for any volunteers to drop in.