The home secretary has told the BBC the Labour Party will not be "fractured" once Tony Blair steps down as leader.
John Reid said the party leadership would remain united
John Reid, who has not ruled out making his own leadership bid, said Labour was unified going into the local elections, and would remain so afterwards.
He refused to say whether it was a "done deal" that Chancellor Gordon Brown would succeed Mr Blair.
But he added: "There will not be a fracturing... there will be a coming together of the Labour leadership."
Mr Blair is widely tipped to step down within days of elections in Scotland, Wales and English local authorities, to be held on 3 May.
Asked whether it was a "done deal" that Mr Brown would replace him, the home secretary told the BBC he was not going to "blow up" the "bubble of hysteria" which surrounded the Labour leadership.
He told BBC One's Sunday AM programme: "The election that matters to me is the election which places before the British people the choice between Conservatives and Labour.
"That is the important election.
"What I am saying is that beyond that election, I believe that the purpose and the practice of unity which will lead us into it will extend beyond it, and it will be a substantial one - a coming together - on the basis of a common view and a common direction for the future."
Asked whether he meant he would not be mounting a bid for the leadership himself, Mr Reid said he would not speculate on the leadership elections.
He said the Labour leadership was in "total agreement" on issues that would define the next 10 years - like the environment, security, mass migration and terrorism.
"We have stood together over the past 10 years. We took the accolades together, we now must take responsibility together if we are declining in the polls and will forge a future together in the spirit of unity and on the basis of substantial policy."
Mr Brown remains the front-runner to succeed Mr Blair, only two other candidates from the left of the party - Michael Meacher and John McDonnell - have announced their intention to run.
The chancellor is the favourite to succeed Mr Blair
All candidates need 45 nominations to be entered onto the ballot - Mr Meacher and Mr McDonnell have agreed the one with fewer nominations will step aside.
Mr Brown's campaign says he already has the support of 217 Labour MPs - more than half of the Parliamentary party.
Meanwhile, the prospect of a Cabinet-level challenge to Mr Brown has all but disappeared after Environment Secretary David Miliband insisted he was "not a candidate".
The Sunday Times has claimed that Mr Blair will back Mr Brown as his successor after Mr Miliband indicated he would not run - even if Mr Reid and his predecessor as home secretary Charles Clarke decide to mount leadership bids themselves.