SALISBURY MP Robert Key today became the latest MP to announce he was quitting Parliament at the next general election.

The 64-year-old former minister said he was quitting the Commons after receiving medical advice. He has osteoarthritis and underwent spinal surgery three years ago.

Mr Key, a member of the Defence Select Committee, will vacate the safe Tory seat, where he was re-elected with a majority of 11,142 in 2005.

He is one of more than 120 MPs who have declared that they will not stand at the election expected next spring, many prompted by the expenses scandal earlier this year.

Mr Key drew less in allowances than most of his colleagues but recently repaid £530 after being asked to do so by Sir Thomas Legg, who conducted an audit of claims.

Sir Thomas felt that Mr Key should have spent less than the £1,650 he did for an oven at his second home.

Mr Key told the executive council of Salisbury Conservative Association yesterday that he had initially intended to stand again - and had been re-adopted as a candidate.

"However, I have recently had medical advice - and I will take it," he went on.

"Three years ago I had spinal surgery. It was wonderfully successful. But the underlying cause was osteoarthritis so the only certainty is that my health will get worse, not better.

"It would be unfair to Salisbury constituency, unfair to the Conservative Party and unfair to my family to stand again, knowing the risk I would be taking."

Mr Key has been MP for Salisbury since 1983 and was a parliamentary private secretary in Margaret Thatcher's government.

The former teacher became a junior minister for the environment and, later, transport under John Major. He served as a shadow minister between 1997 and 2003.

Mr Key said: "This has been a hard decision to take with the prospect of a Conservative government within reach.

"I have wished David Cameron great success next year. I have supported his leadership from the start. He will make a great Prime Minister."