A police clerk implicated in a sex smear by a chief constable has won a massive payout over the claims.

Jayne Thwaites is now set to receive more than £100,000 after launching a damages action against Cleveland Police and Cleveland Police Authority.

The force will also have to pay a further £60,000 to cover the 37-year-old's legal costs.

Ms Thwaites, from Hartlepool, Teesside, alleged that former Chief Constable Barry Shaw - who retired last year - was behind the leaking to newspapers of rumours of a "fictitious" affair with former Middlesbrough CID chief Ray Mallon.

Ms Thwaites, who quit her job last June, also claimed she had been followed by MI5 agents on Mr Shaw's instructions.

She claims the moves were part of a bid by the former chief, who retired in March, to discredit Mr Mallon, 48, at the height of the Operation Lancet malpractice probe.

Mr Mallon - dubbed Robocop for his Zero Tolerance approach to law enforcement - quit the force following the lengthy £5m inquiry into the alleged supply of drugs to criminal informants in exchange for confessions.

Mr Mallon, who always maintained his innocence, was later elected as Middlesbrough's first democratically elected mayor.

Cleveland Police and Cleveland Police Authority last November confirmed they were considering a claim by Ms Thwaites.

The former clerk, who was represented by Middlesbrough law firm Watson Woodhouse, has declined to comment because of a strict confidentiality clause in the agreement.

But in a previous interview she did speak of the trauma the case had caused.

She said: "I have never had an adulterous affair with anyone and it is extremely distressing to have to put up with such malicious rumours. "All I have ever wanted to do is get on with my life and the job I love, but that has been impossible."

In 2002 Cleveland Police Authority decided not to take disciplinary action against Mr Shaw, despite a damning report from South Yorkshire Chief Constable Mike Hedges.

Mr Hedges headed Operation Diamond, a lengthy investigation supervised by the Police Complaints Authority, into claims of dirty tricks allegedly designed to discredit Mr Mallon and derail his political ambitions.

In addition to Ms Thwaites's claims of security service involvement and sex smears, Mr Hedges also looked into claims by former public affairs manager Jo Malone that the force was behind the leaking of a sensitive Lancet report to a national newspaper.

His final report, considered in closed session by Cleveland Police Authority, recommended Mr Shaw should be held "culpable for abuse of power and breach of confidence".

Last year Ms Malone, 39, received an out of court settlement of £40,000 plus £60,000 legal costs.

Miss Malone quit the force in disgust in 2000 after exposing the dirty tricks campaign against Mr Mallon and Miss Thwaites and refusing to become part of it.

A Cleveland Police spokesman said yesterday: "We have no comment to make." The Police Authority has also declined to comment.