Gordon Brown is facing pressure from some MPs who want him to step down. What has happened and how serious it is for the PM?
Thirteen Labour MPs have made public calls for a leadership contest to take place. Several wrote to the General Secretary of the Labour Party demanding leadership nomination papers, which they believe should be sent out annually to all MPs ahead of the party conference. Scotland Office minister David Cairns resigned on Tuesday, saying the time had come "to allow a leadership debate to run its course".
Who are the rebels?
The first name to emerge was Siobhain McDonagh. She was quickly sacked from her position as an assistant Whip. She was soon joined by others including former ministers like Fiona McTaggart, Barry Gardiner and Janet Anderson. Less surprising rebels are Frank Field and John McDonnell who've been saying for months that Gordon Brown must go. Mr Cairns is the highest ranking member of the government to have so far joined the rebels.
Why are they unhappy with Mr Brown?
Some want the party to change direction and adopt more left-wing policies. Others believe Gordon Brown is the problem because he's unpopular with voters and they're no longer listening to Labour's message. They say many MPs are discussing the leadership issue in private and say it is time to clear the air and have an open contest. Several of the rebels were close to Tony Blair.
What are the party's rules for challenging a Labour prime minister?
To trigger a leadership contest 70 Labour MPs would have to nominate a candidate for a leadership contest. The person they nominate would have to accept their nomination.
What have Mr Brown and/or his aides said about the situation?
Some in Downing Street have dismissed the rebels as Blairites who've "never liked Gordon". Officially Number Ten says Mr Brown welcomes a debate in the party and he told Cabinet ministers they shouldn't personally condemn the rebels.
What have Mr Brown's senior ministers said?
Business Secretary John Hutton said he wouldn't condemn colleagues who were calling for Labour to do better and set out a stronger vision. Chief Whip Geoff Hoon ruled out a contest saying he didn't "think at this stage it's appropriate". Foreign Secretary David Miliband said he expected Gordon Brown to lead the party into the next election. Chancellor Alistair Darling said he had every confidence in the PM who, he said, was the "right person to lead this country and to lead our party".
What are the key dates/events to watch out for now?
On Tuesday Labour's ruling body the NEC is meeting and one MP on the committee says she'll raise the issue of nomination papers. Labour Party rules say papers should be sent out every year before the party conference. In reality this hasn't been done for ten years. The question of Mr Brown's leadership is set to dominate the Labour Party conference, beginning in Manchester on Saturday. The next electoral test will be a by-election in Glenrothes - in either October or November.
Is Mr Brown likely to survive?
In the short-term yes. MPs speaking out in this way is clearly damaging to the Prime Minister as he attempts to reassert his authority, but at this stage it is wounding, not fatal. Everything would change if Cabinet ministers decide to resign. There is also the question of a candidate - there is no agreement amongst MPs about who would be the best replacement for Mr Brown. Many are willing to give their leader another chance at next week's conference, hoping he can do something to improve his poll ratings.