But let's consider who has put their heads above the parapet so far?
Janet Anderson (MP for Rossendale and Darwen) called for a debate and a contest for a new leader of the party over the weekend.
Ex-minister George Howarth (MP for Knowsley North) told Gordon Brown "you're the problem" back in July and made a request for nomination papers to be sent out two weeks ago.
Graham Stringer (MP for Manchester Blackley) wants to "sort out the leadership issue once and for all."
Gordon Prentice (MP for Pendle) got the ball rolling back in July by brazenly calling for the PM to quit.
Greg Pope (MP for Hyndburn) has been quoted in today's Sunday Times "we can't go on like this pretending there isn't a problem.... Party members need to have a say."
Frank Field (MP for Birkenhead) has said that the Cabinet needs to find the courage to rescue the party from certain electoral annihilation. This was after criticising Gordon Brown and openly saying that the only strategy left was a change in leadership.
What do all of the above MPs have in common?
The constituencies they represent all have a remarkable proximity to Blackburn, the constituency of one Jack Straw.
It's pretty clear that Jack wants to be the Straw that breaks Brown's back.
UPDATE: Having read a comment on the utterly fabulous Guido Fawkes' blog, I think it might be clear who is being primed to step into the breach:
Working for one of the Progress article MPs, I can tell you that the fact women have been coming forward to knife the PM has a lot to do with a certain female deputy leader.
Shame, you can't get a good pun out of Harriet Harman.