Ex-Labour leader Neil Kinnock has said he detects the hand of Rupert Murdoch in Tony Blair's decision to hold a referendum on an EU constitution.
Mr Kinnock is a an EU commissioner and ex-Labour leader
The suggestion prompted Downing Street to issue a denial saying the prime minister had not talked to the media mogul about the issue "recently".
"I don't recognise that suggestion at all," a spokesman said.
Mr Blair formally announced on Tuesday that there will be a referendum on the planned constitution.
Mr Kinnock, an EU commissioner, has expressed opposition to the plan to put the constitution to the vote.
During a regular briefing to journalists, the Number 10 spokesman was pushed about whether Mr Blair had discussed a referendum with Mr Murdoch.
He said: "He hasn't talked to Rupert Murdoch recently about this issue.
"We don't give precise details of conversations. Recently means recently," he added.
The spokesman then said that the prime minister had "routine and regular" talks with a close of Mr Murdoch, Irwin Stelzer.
The Australian-born tycoon has an extensive media empire
The Conservatives and Liberal Democrats have welcomed the Mr Blair's U-turn on a referendum.
But Mr Kinnock said the constitutional treaty would not change the way Britain was governed.
He told BBC Radio 4's Today programme that Mr Blair was responding to "political circumstances" and said a 'No' vote could damage Britain's position in the EU.
"What could be destabilising, and grievously so, is a 'No' vote that we were
putting in question our engagement in the Europe defined by the shape of the
constitutional treaty," said Mr Kinnock.