DOWNING Street has declined to comment on reports that GCHQ, the UK Government's eavesdropping centre, organised surveillance of foreign politicians to an international summit in London despite Turkey demanding answers from Britain's ambassador.

No 10 insisted it did "not comment on intelligence issues" in a clear bid to downplay the issue, which will embarrass David Cameron as he hosts leaders from the world's most powerful countries at the G8 summit.

The claim is that foreign politicians and officials who attended two G20 summits in London in 2009, during the government of Gordon Brown, had their phonecalls intercepted and their computers monitored at the behest of their British hosts.

A Foreign Office spokeswoman confirmed the Turkish government had raised the allegations with Sir David Reddaway, the UK ambassador to Ankara, but stressed that he had not been summoned to answer questions in person.

The Prime Minister refused to answer questions on the row as world leaders arrived for G8 summit, saying: "We never comment on security or intelligence issues and I am not about to start now."

His spokesman said he was not aware the issue had sparked a row among the summiteers.

It was suggested that in 2009 the Turkish finance minister – and possibly as many as 15 other members of his party – were among those targeted at the G20.Leaked documents were said to suggest that the security service operation was sanctioned at a senior level in the Brown Government and that the intelligence obtained was passed to ministers.

GCHQ has previously said in relation to an earlier report about its involvement in the operations of America's National Security Agency that its work was carried out "in accordance with a strict legal and policy framework which ensures that our activities are authorised, necessary and proportionate".