Former cabinet minister David Blunkett has demanded that Labour Party members "get a grip" of themselves as their annual conference gets under way.
Speculation continues as to when Tony Blair will leave office
He said cabinet colleagues risked damaging the party by focusing too much on the leadership issue.
Mr Blunkett warned that if tensions within the party did not end, Labour ran the risk of "destroying" itself.
His comments come after Prime Minister Tony Blair confirmed that he would leave his post within a year.
Many within the party fear the return of Labour in-fighting may well damage its popularity.
Mr Blunkett said that even two days ago, people still thought the conference might turn into a "bun fight".
However, he said there was now a spirit in the party to get its act together.
He said: "The most we can ask of people now is that they get a grip of themselves.
"The least we can ask of them is that they respect each other and that they act in the way that they're always preaching to other people about mutuality, about fraternity, about the kind of things that my party and I have been talking about since I've been a member and too often don't practice."
Former government communications chief Alastair Campbell said Labour must show it is "in touch" with the public.
He said it was important for Labour to show this week that the recent problems were "nothing more than a spasm."
"What matters is that this week the Labour Party is seen by the public to be back in touch with them and their concerns and not going down the media agenda of let's talk about Tony, Gordon, Harriet Harman, Jack Straw, Peter Hain and all the rest of it."