Sir Paul said his wife Heather had nothing to do with the decision

The former Beatle said he made the move because the "professional standards" of Mr Baker, a longtime friend as well as PR man, had fallen in recent months.

Sir Paul also denied what he said were "particularly sad" claims that his wife Heather wanted Mr Baker out.

Mr Baker, a former newspaper reporter, had dealt with Sir Paul's music and Beatles developments over the years. He declined to comment.

His behaviour has not reached the professional standards I had come to expect Sir Paul McCartney

In a statement, Sir Paul said: "I find it very sad that after years of friendship, my publicist Geoff Baker and I are parting.

"Over the past few months, his behaviour has not reached the professional standards I had come to expect from Geoff and it is with regret that I am forced to end our relationship.

He added: "It is particularly sad that he has chosen to attempt to implicate my wife Heather in this business and I can say now that she has had absolutely nothing to do with this.

"In fact, she has always been a great supporter of his.

Assault allegations

"This is purely between Geoff and myself and I am sad to see it end in this way."

In September last year, Sir Paul "jokingly" sacked Mr Baker after an incident during a visit to David Blaine's box on London's South Bank.

Mr Baker, admitted he had "stupidly" tipped off a photographer about the visit. Sir Paul had sacked him on the spot but later reinstated him.