Sir Paul McCartney had daughter Beatrice with Heather Mills in 2003

Sir Paul McCartney has revealed that he's quit his 50-year cannabis habit for the sake of his 8-year-old daughter Beatrice.

Sir Paul, 69, first started using the drug after being introduced to it by Bob Dylan in the 1960s and ex-wife Heather Mills says he was still a regular user during their 6-year marriage, which ended in 2008.

'I smoked my share,' admits Sir Paul.

'When you're bringing up a youngster, your sense of responsibility does kick in, if you're lucky, at some point.'

Sir Paul has fallen foul of the law several times over drug-related offences.

He was arrested twice for cannabis possession in the 1970s and was deported from Japan in 1980 when marijuana was found in his suitcase.

He's also experimented with LSD and other drugs.

'I did a lot, and it was enough,' Sir Paul tells Rolling Stone.

'Enough's enough - you just don't seem to think it's necessary.'

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Anna Duff