CLEVELAND Police Authority last night pledged to help Ray Mallon in the costly battle to clear his name - after the suspended detective decided to quit.

Detective Superintendent Mallon said he was stepping down because he could not afford to defend himself against the disciplinary charges he faced.

His legal insurance through the Superintendents' Association has run out and he fears that a lengthy hearing would cost £120,000 - money he would not recover even if he won.

Det Supt Mallon intends to stand as Middlesbrough's first elected mayor if the new post is backed in a referendum in October.

But last night, Cleveland Police Authority said it would investigate ways of helping his defence.

Chairman Ken Walker said: "I believe it is important to bring the disciplinary proceedings to a proper conclusion.

"I have asked officers of the Police Authority to examine the situation and report as to whether there are ways in which it would be possible to ensure that financial pressures affecting Mr Mallon could not be seen as a valid reason for preventing the completion of the disciplinary process."

It also appeared that Det Supt Mallon's resignation might not be accepted by Chief Constable Barry Shaw.

Mr Shaw may insist he stays until the disciplinary hearing is concluded. Under Police Regulations, no officer may, without the consent of the chief constable, give notice to the police authority that he intends to resign or retire.

If Mr Shaw blocks the bid - and insists Det Supt Mallon stays until the disciplinary hearing, due to go ahead in October, is concluded - then his hopes of becoming mayor will be dashed.

During a press conference yesterday he said: "I have been approached by a number of people and asked to stand. To do that I must leave the force now."

Lawyers acting for Det Supt Mallon handed in his resignation at Cleveland Police headquarters yesterday.

A force spokesman said: "The letter will now receive appropriate consideration from the chief constable."

Sources close to the force confirmed last night that permission to leave was by no means a foregone conclusion.

The high-profile policeman was suspended for what Cleveland Police's then head of complaints and discipline, assistant chief constable Robert Turnbull described "alleged activity which could be construed as criminal".

Although the Crown Prosecution Service decided last year not to proceed with any criminal prosecution against him, he remains suspended pending the disciplinary hearing.

Det Supt Mallon said he would not attend his hearing.

"I have become the most investigated officer in the history of the British police service," he said. "Every expense claim I submitted since 1995 has been scrutinised.

"Criminals I locked up 20 years ago have been interviewed and my links with the media, my private life and the lives of my two daughters and friends have been probed. MI5 even carried out surveillance.