by Jackie Storer
political reporter, BBC News at Labour's conference
Union leaders backed away from a showdown with Gordon Brown because they did not want to ruin his first Labour conference as leader, it has emerged.
Mr Brown's plans were criticised at the TUC earlier this month
Unions had been expected to clash with Mr Brown over controversial changes to conference voting rules.
But Derek Simpson, joint leader of the UK's biggest union Unite, said they had wanted to avoid "a bloodbath".
Unison leader Dave Prentis said the most important thing was for the unions to "speak with one voice".
At a fringe meeting in Bournemouth, the union leaders defended their decision not to oppose Mr Brown's bid to end the submission of emergency motions for debate at Labour's annual conference.
Some Labour MPs, constituency parties and unions accused the prime minister of trying to stifle debate.
But unions and constituency Labour parties overwhelmingly backed the move in a conference vote.
Mr Simpson told the fringe: "We have had to get into this position because we don't want a bloodbath at this conference, the first conference.
"I think the correctness of that has been demonstrated today, a good start."
Mr Simpson said the new Labour leader had made an "excellent" speech. "He certainly is no disappointment. He hasn't fallen on his face. Many of the things he said found a resonance.
"He wasn't too specific about some issues but touched a number of them and I think obviously set the hares running about whether he's going to call an election.
"Now I'm prepared to take bets that he won't call it in the next week."
But Mr Simpson stressed that whatever the differences were between the unions and Labour leadership "there's absolutely no doubt that none of us would benefit from the return of a Tory government.
"We have get a fourth Labour term."
The only significant protest to the changes to voting rules on emergency motions came from former minister Michael Meacher who warned they would be "a huge step backwards" for the party and reduce it to "virtual impotence".
The unions - which have inflicted a string of embarrassing defeats on the leadership over issues such as pensions and housing in recent years - will still be able to table motions but, crucially, not vote on them.
They would instead be referred to the party's national policy forum and discussed in private.
Another key change would see Labour's draft manifesto put to a ballot of all members on a one-member, one-vote basis.
The unions as a block hold 5% of the vote at conference.