Updated

Prime Minister Tony Blair faced new murmurings of revolt within his party Tuesday, raising the stakes in his frantic efforts to line up support for a second U.N. Security Council resolution to authorize war on Iraq.

Warnings of a grass roots rebellion followed a threat by one of Blair's Cabinet members, International Development Secretary Clare Short, to resign if Britain joins the United States in an attack without U.N. backing.

With France and Russia threatening to veto any new resolution, Britain has signaled flexibility on a proposed March 17 deadline for Iraqi President Saddam Hussein to fully comply with disarmament demands. Despite the veto threats, Britain still hopes to muster nine "yes" votes from the 15-member council.

Lawmaker Tam Dalyell, one of Blair's most caustic critics within the Labor Party, said Tuesday that his local Labor Party organization was one of several which have drafted resolutions calling for the prime minister to consider resigning if Britain goes to war without a U.N. mandate and a prior vote by the House of Commons.

"If there is a second resolution, I have to say that in the view of many of my colleagues -- not mine -- it's very different.," said Dalyell, the longest-serving member of the House of Commons.

Labor Party chairman John Reid dismissed talk of revolt as coming from "the usual suspects" on the left of the party.

"I've met thousands of party members and I tell you the stories about 40,000 people leaving the Labor Party are a lie, stories about bonfires of party cards being ripped up are a lie. Some of these stories have been put about by people opposed to Tony Blair for 14 years," Reid said in a British Broadcasting Corp. television interview.

Blair finds himself in an excruciating dilemma between his passionate support for firm action to disarm Iraq, and the deep skepticism within the country and throughout Europe.

A poll published Tuesday in The Times newspaper said 52 percent of respondents would back British involvement in a war only if there was a new U.N. resolution. A month ago, the figure was 62 percent. The same poll found that Labor's popularity has sunk to the same level as the opposition Conservatives.

Chris Smith, a former member of Blair's Cabinet, urged the prime minister to break ranks with the United States.

"I hope that even at this last stage he could have the courage and the statesmanship to say 'no, we are not going to go ahead with this', even if the Americans decide to do so," Smith told BBC radio.

Smith was a leader in a major rebellion by ordinary members of Parliament against Blair's policy. He was joined by 121 other Labor lawmakers last month in voting for an amendment which called the case for war "unproven."

Blair loyalists easily defeated the amendment, but opponents say that more lawmakers would be prepared to vote against the government if it doesn't get the U.N. resolution.

"All the way through Tony Blair has taken the party with him on this promise of the U.N. route," said Mark Seddon, a member of Labor's National Executive Council. "To risk breaking international law, to risk the future of the U.N., and breaking the party too ... would probably mean that there would be support from a good number of MPs and trade unionists" to challenge Blair's position.