Fewer than 10,000 signatures are required to trigger a fresh poll on whether Brighton and Hove should have a directly elected mayor.

The figure was revealed by the city council as part of its legal obligation to re-open the question every five years.

In October 2001, 62 per cent of voters rejected the introduction of an elected mayor in Brighton and Hove.

Conservative councillors, who led the No campaign five years ago, vowed to oppose any new attempt to seek a referendum to replace the existing committee system with a mayor and cabinet.

Brian Oxley, the party's finance spokesman, said: "We agree with reports that highlight the need for more powers to be given to local government.

"But why does Government assume that changing the balance of power automatically means having elected mayors?"

Fellow Tory Ann Norman said: "The council's existing committee system is vital in ensuring that everyone's voice is heard in the policy-making process.

"We are worried an elected mayoral system could lead to more centralised decisionmaking, and a less democratic system of local government."

Conservative group leader Garry Peltzer Dunn said: "In 2001 the anti-mayor campaign team, with myself as joint-chairman, fought to bring back true democratic local government to Brighton and Hove, and won.

"I give due notice that the Conservative group will oppose any attempt to once again curtail full local democracy."

The Tories have proposed a motion to be debated at the council meeting on March 16 which calls on residents not to sign any petition in favour of a fresh referendum.

The council will be asked to show "concern that a costly referendum will harm council taxpayers if it changes nothing, and harm local democracy if it leads to an elected mayor".

The last referendum cost council taxpayers £170,000 Under the Local Government Act 2000 the signatures of five per cent of Brighton and Hove's electors can trigger a referendum on an elected mayor every five years.

On the latest count this would require 9,465 people to sign a petition between April 1 2006 and March 31 2007.

Labour council leader Simon Burgess indicated there was little chance of a new pro-mayor campaign gaining support.

He said: "I am not interested in there being an elected mayor.

"There was a clear ballot against the idea and as far as I'm concerned the people have spoken."

But Labour peer Lord Bassam, who campaigned for a Yes vote five years ago, said introducing an elected mayor was "something Brighton and Hove will have to think about in future".

Hinting that he might put himself forward as a mayoral candidate in any future election, he said: "Elected mayors are highly visible and directly accountable to electors.

"They are big enough to negotiate with Government, cut deals and make things happen by cutting through bureaucracy."