The appointment of Brighton and Hove’s new mayor was disrupted last night by a row about rumours of an under-fire councillor’s resignation.

Green Party convenor Bill Randall sparked the argument at Hove Town Hall as Councillor Ann Norman prepared to accept the ceremonial chains of office during Brighton and Hove City Council’s annual meeting.

Coun Randall said the Greens were unhappy at rumours that Conservative councillor Paul Lainchbury would be resigning from the council in the next few days.

He said the resignation, which his own party and Labour have called for, had been delayed so that the Conservatives could install a mayor of their choice.

Coun Randall said: “We have no doubt at all Ann Norman will make an outstanding mayor.

However, we are unhappy with the process with which this has happened. We believe the mayor will be supported with the vote of someone who is about to resign from the council.”

Coun Lainchbury’s seat on the council is crucial because it tips the balance of power in favour of the Conservatives.

If he had resigned ahead of yesterday’s meeting, the opposition parties could have voted in a block to install a mayor from one of their own groups.

The mayor has a casting vote on issues when council voting is tied.

The Conservatives currently control the administration by the smallest of margins.

They have 26 of the 54 council seats, Labour has 13, the Green Party has 12, the Liberal Democrats two and there is one independent, Jayne Bennett.

For the past two years, the Conservatives have been able to win key votes with the backing of Coun Bennett.

If Coun Lainchbury were to resign, the opposition parties would be able to vote together to overrule them.

He has faced calls to step down after it was revealed he had failed to attend any meetings of the council’s audit committee for a year. His fellow ward councillor Melanie Davis has also accused him of being absent from dozens of assemblies of residents’ associations and action groups. Coun Lainchbury sat quietly through the row. At the end of the meeting he left quickly and did not join other members for a special reception.

Conservative council leader Mary Mears has denied rumours that her group has been preparing for a by-election in Coun Lainchbury’s Goldsmid ward in Hove and that they have blocked attempts by him to resign.

She criticised Coun Randall for his attack yesterday, cutting him off as he spoke at a meeting attended by invited dignitaries.

Coun Mears said: “This is a civic occasion. I find it quite crass that, with visitors to the town hall here, a leader of a political group would try to make a political point today.”

Coun Norman did not enter into the argument. When she accepted her position she gave thanks to Conservatives Geoffrey Theobald and Coun Mears who had proposed and seconded her and Labour and Lib Dem leaders Gill Mitchell and Paul Elgood who endorsed her appointment.

She said: “I thank Bill Randall for parts of his endorsement.”

She takes over the 12-month role from Garry Peltzer Dunn.

Coun Norman, who is married to fellow councillor Ken Norman, was born and has lived her whole life in Brighton. She has represented the Withdean ward on the council since 1995.