THE Ulster Unionist mayor of Derry has described as "deplorable" a decision by the city's Nationalist controlled council to invite Mr Martin McGuinness of Sinn Fein to April's civic ball.
"The thought of Martin McGuinness dancing in the Guildhall as an invited guest of the council horrifies unionists," said the mayor, Mr Richard Dallas.
The Sinn Fein negotiator's name has been included on the council's civic list at the behest of his party backed by the council's majority SDLP councillors.
Mr McGuinness's inclusion, means he will now be officially invited, as a guest, to all council civic receptions.
Other members of the list include the city's RUC chief superintendent, the Lord Lieutenant and the High Sheriff.
"This could lead to a total boycott of all civic functions by unionists," said Mr Dallas.
"We will have to examine each invitation individually to ensure that any unionist representation at a civic reception does not give McGuinness any credibility. Sometimes we may have to attend to ensure that the unionist perspective is put," he said.
The SDLP council leader Mr Pat Devine, said his party backed Sinn Fein's proposal to avoid giving what he called martyrdom.
"This decision is tailor made for one man, Martin McGuinness. It will not spread throughout Northern Ireland, nor is there any principle attached to it.
"Sinn Fein were looking for us to exclude them from the civic list. They were seeking martyrdom and we decided not to give it to them.
"It's now up to them to explain to their supporters why they so much want to join a list which includes representatives of the queen," said Mr Devine.
Sinn Fein's successful proposal to amend the civic list to include all citizens who hold elective status in the council area on the basis of parity and esteem is based on Mr McGuinness's election to the Northern Ireland Forum. Last December unionists accused Mr McGuinness of gate crashing a civic function for US Congressman Joe Kennedy.