Sir Mick Jagger says his jail stint was "nothing to be cavalier about", even though it had "lighter" moments.

The Rolling Stones rocker and his bandmate Keith Richards were both imprisoned in 1967 on drugs charges. The way they were treated caused an outcry, with claims the justice system was unduly harsh on them due to their celebrity status.

Keith has spoken about the experience on several occasions, with Mick disagreeing with him on how easy the situation was.

"It was nothing to be cavalier about. It was terrifying," he told Q magazine. "But at the same time it did have its macabre, lighter moments. You know, we weren't living in a police state. Everyone wasn't against us. We had a lot of support in the press as well."

Mick was sentenced to three months in jail for possessing four amphetamine pills, but later appealed. The prospect of being locked up is something which has stayed with the 69-year-old star ever since.

"[It was] scary," he recalled. "We were facing the prospect of a few months inside. Looking back it was all a bit... extreme. It was unnecessary and a waste of everyone's time and money. It was a bit silly, really."

The star remains astounded by how successful the rock band has been. They are gearing up to play the iconic Glastonbury music festival in the UK this year, the first time they have done so.

Mick is planning to be there all weekend and will camp with his family. He is taking the show very seriously and hopes to attract new fans while there.

"It never gets easier. You've always got to prove yourself. You can't rely on anything you've done in the past," he warned. "Every time you play live, it feels like you're finding your way again. Then you look at Keith or Charlie [Watts, drummer] and think, 'Oh, it's OK.'"