Downing Street has dismissed as "complete rubbish and utter drivel" claims last night that its staff had hacked into the BBC's computer system in an attempt to try to influence negative news items before they were broadcast.
The allegations, contained in a new book by John Simpson, the corporation's world affairs editor, will renew the row over New Labour spin.
Mr Simpson, in his book News From No Man's Land which is quoted in today's Sunday Telegraph, claimed a colleague had noticed that when he wrote a script for a forthcoming news bulletin "he would be rung up by Downing Street before it was broadcast and lobbied on a point or two". "This didn't happen just once or twice," he said.
BBC Radio 4's World At One programme was also telephoned by No 10 officials to complain about items it was planning to run, Mr Simpson's book alleges. The Sunday Telegraph also claims that the BBC, alerted to concerns that someone was getting into its system, investigated the matter and upgraded security.
But a spokesman for the BBC said last night: "We don't discuss issues of security. However, we are continually reviewing the security of our systems and we always aim to maintain complete impartiality in our political journalism."
Computer hacking was made illegal under the Computer Misuse Act of 1990. But the newspaper claims that the BBC was forced to investigate alleged breaches of the act in 1997 after Labour's election victory amid tension over the new Government's apparent attempts to "manage" news coverage and put pressure on journalists and editors to give it favourable coverage.
The Tory frontbencher David Davis said he would be contacting the chairman of the BBC Board of Governors to demand the publication of the BBC's internal inquiry. "If John Simpson's allegations are correct, then No 10 and Labour Party staff seem to have been complicit in a criminal act," he said. "At the very least, it would seem that there has been systematic action by No 10 and the Labour Party to break the BBC's charter which requires impartiality."