Organisers of a campaign for a "yes" vote in a referendum to decide whether Middlesbrough is to have an elected mayor, are being challenged "to come clean".

The call follows the launch of a campaign leaflet featuring a photograph of ex-Middlesbrough CID head, Detective Superintendent Ray Mallon.

The caption under the photograph, which shows Mr Mallon standing beside housewife June Goodchild, a supporter and spokeswoman for the "yes" vote campaign, says: "Supporters of the mayor for Middlesbrough Campaign."

Det Supt Mallon declared his desire to be elected mayor of Middlesbrough, and his plans to campaign for a "yes" vote, in August - together with his attempt to resign from Cleveland Police.

Cleveland Chief Constable Barry Shaw has refused to accept the resignation, while Det Supt Mallon - although cleared of any criminal wrongdoing - faces 14 disciplinary charges arising from the Lancet inquiry into claims of police corruption.

Councillor Ken Walker, the leader of Middlesbrough Borough Council, said: "I have made my personal position perfectly clear; I favour having an elected mayor, because I believe it will be of benefit to the town.

"I have also made it crystal clear that I have no interest in seeking election to the post myself. However, I think it is fair to ask those who have produced this leaflet to come clean over what they are really about.

"It is really insulting the intelligence of the public to claim that this is simply about the principle of whether to have an elected mayor - and then include the picture of an individual who is a self-proclaimed would-be candidate for the post, under the guise of a supporter."

Mrs Goodchild said: "The Mayor for Middlesbrough campaign would be going ahead whether or not Ray Mallon had put his hat in the ring. He is the most high-profile supporter of having an elected mayor, and it would have been misleading not to mention him at all."

Mr Mallon's disciplinary hearing starts next week