A group of leading British scientists including Nobel-winning geneticist Paul Nurse warned leaving the European Union could threaten research funding, in a letter published in The Times newspaper on Friday.

"It is not sufficiently known to the public that the EU is a boon to UK science and innovation," read the letter, also signed by astronomer Martin Rees and Nature journal editor-in-chief Philip Campbell.

"Freedom of movement for talent and ambitious EU science funding programmes, which support vital, complex international collaborations, put the UK in a world-leading position," the letter continued.

"We wish to make known our support for the EU, its scientific direction and our continued membership."

In a bid to appease Eurosceptics in his own party and counter the rise of the anti-EU UK Independence Party, Prime Minister David Cameron has promised to hold an in-or-out referendum by 2017 at the latest.

Many leading companies including the Confederation of British Industry, the big business lobby, have spoken out in favour of membership in recent days.

Britain won over 1.0 billion euros ($1.1 billion) in funding between 2007 and 2014 and European exchange programmes allow thousands of students to move between Britain and the rest of the EU every year.