Taxpayers could be forced to pay an extra £160,000 if a referendum on a directly-elected mayor is imposed on the city.

Brighton and Hove Council leader Lynette Gwyn-Jones has warned opponents the Government could still force the authority to organise a vote.

Last week, rebel Labour councillors joined with the Opposition to defeat plans by the leadership to hold a referendum on May 3.

The date was chosen to save money in organisation and increase turnout because it is likely the General Election will be held the same day.

Coun Gwyn-Jones said: "By voting against these proposals, opposition councillors have shown themselves to be utterly undemocratic and could be adding more than £160,000 to tax bills in the year ahead."

She said under the Local Government Act, all councils had to consult people on new ways of running their authority.

The leader added: "If there appears to be public support for an elected mayor, then the council must organise a referendum.

"We have done the consultation. The support appears to be there, so we now want to test this properly in a referendum."

Coun Gwyn-Jones added: "Now it seems councillors in the opposition parties think it is only they who should decide. This is a disgraceful denial of basic democracy."

She said ministers could choose to impose a referendum on councils which did not send in their modernisation proposals by June.

But Tory deputy leader John Sheldon said: "Coun Gwyn-Jones tried to bulldoze through proposals and councillors were expected to support them even though they and the public had not been properly informed."

He said people would have been asked if they wanted to have an elected mayor without being told what all the alternatives could be.

Coun Sheldon said: "The reason councillors from all parties voted against the proposal was to ensure the referendum vote was not rushed through on May 3 but was held later when all the information would be available."

Green councillor Keith Taylor said: "The vote was not against holding a referendum itself. Councillors rejected only the proposals of what questions should be put to the electorate."

Former Labour councillor David Newland of the Socialist Alliance, said: "This decision must not be rushed. It is far too important."