The media mogul is toying with the idea of switching sides

His UK papers include The Sun and The Times, and since 1997 he has been lending his support to Tony Blair.

But in an interview with his paper The Australian, Mr Murdoch was asked if he could see himself backing Mr Cameron next time. He replied: "Oh yes."

Mr Murdoch also warned Gordon Brown if he succeeds Mr Blair not to "cheat" the British public with a snap election.

Mr Murdoch, who is a naturalised American after giving up his Australian citizenship, said British voters had the right to a chance to compare a Gordon Brown premiership with Mr Cameron's leadership of the Conservatives.

Mr Murdoch told The Australian: "We've been a very big supporter of Tony on big issues, he's been a very courageous world leader. We've also been critical of him on other things like Europe.

HAVE YOUR SAY Murdoch should not have disproportionate influence over ANY political party John Fairlie, Bristol Send us your comments

"But, for no reason other than the dynamics of British politics, we would like to see at least a year to 18 months stand-off between Gordon Brown and David Cameron so we can decide which of those most coincides with our views.

"Those two are going to decide the next election and I think the British public would be cheated if they only got a month or two's warning."

Mr Blair is expected to attend a global gathering of executives of Mr Murdoch's News Corporation in California next month.