Proposals to limit the Mayor of London's time in office to a maximum of two terms have been rejected by MPs.
Ken Livingstone has been elected twice as mayor
In an amendment to the Greater London Authority Bill opposition peers in the House of Lords wanted to set a two-term limit for anyone holding the office.
The Lords amendment was rejected without a vote.
Mr Livingstone is to stand for re-election next May and if successful he will serve his third term as Mayor of London.
During debate on Lords' amendments to the Greater London Authority Bill, Local Government Minister John Healey said: "The purpose is clear - they can't beat Ken Livingstone at the ballot box so they are trying to bar him from standing at all.
"It should be for Londoners to decide whether they want Ken Livingstone to continue to serve as their London Mayor - not MPs from all parts of the UK and certainly not members of the unelected House in another place."
He added: "We don't agree with the Tories and the Liberals on this and we won't accept this amendment."
Later, Mr Healey urged MPs to reject a Lords amendment seeking to limit the Mayor's powers to set the budget.
Peers want the London Assembly to be able to amend the Mayor's final draft budget with a simple majority rather than the two thirds margin currently required.
For the Conservatives, Robert Neil said: "Their amendment is an improvement to the Bill and we will resist any attempt to remove it."