* Senior Conservative would back British EU exit now
* Lawmakers in Cameron's party planning revolt this week
* Pressure grows amid rising support for anti-EU party
A senior British minister said on Sunday he would support an exit from the European Union if there were a vote on the issue, as Prime Minister David Cameron faces a revolt over Europe from lawmakers in his own party.
Up to 100 eurosceptic Conservative members of parliament are expected to back an amendment this week criticising the legislative plans unveiled by the coalition government last Wednesday because they did not include a bill for a referendum on Britain's continued EU membership.
Ministers have been ordered not to join the rebels but will be allowed to abstain, a sign of the extent of the divisions that have dogged Cameron's party for decades.
Three senior ministers, including Education Secretary Michael Gove, said on Sunday they were ready to abstain.
Gove went further, becoming the most senior Conservative figure to publicly confirm that he would back Britain's withdrawal from the European Union if there were a vote based on the current terms of the relationship.
"I'm not happy with our position in the European Union but my preference is for a change in Britain's relationship with the European Union," said Gove, seen as a possible rival to Cameron. "Life outside would be perfectly tolerable, we could contemplate it, there would be certain advantages."
Cameron came to power in a coalition with the pro-Europe Liberal Democrats in 2010 with a plea to his party to "stop banging on about Europe" - a squabble that helped to bring down his predecessors Margaret Thatcher and John Major.
But the prime minister has come under increasing internal pressure after the party suffered in local elections this month at the hands of the anti-EU UK Independence Party.
Cameron has promised to renegotiate Britain's relationship with the European Union and hold a plebiscite on EU membership in 2017, but eurosceptics want a vote now.
Cameron's plans depend not only on securing more favourable EU membership terms but also on forming the next government after elections in two years. The Conservatives currently trail the opposition Labour Party by around 10 percentage points in surveys.
Gove and other ministers said they fully supported Cameron's stance, but that has done nothing to dim the internal clamour.
Junior Conservatives in parliament would have free rein on whether to back the proposed amendment, but ministers had been instructed to abstain, a government source said.
One unnamed minister told the Sunday Telegraph the fact that Cameron could not even force his cabinet colleagues to vote against the motion showed the prime minister's weakness.
Former senior minister Liam Fox, who ran against Cameron in 2005 for the Conservative leadership, told Sky News he would back the amendment, but described it as "an element of frustration" rather than an overt criticism of the prime minister's position.
While more than 500 business leaders backed Cameron's renegotiation policy in April, saying a new, looser relationship would boost the British economy, others fear his referendum pledge has created uncertainty that will deter investment.