The Rolling Stones frontman arrived with Hall and three of their children - James, 14, Elizabeth, 15, and Georgia, eight - to open the Mick Jagger Centre at Dartford Grammar School.

They could either go to school or come here - so they chose to come here instead

Mick Jagger on taking his children

Jagger and Hall separated in August 1999 after their marriage was declared null and void at the High Court in London, but the couple have remained on friendly terms.

He joked about taking his children: "They could either go to school or come here - so they chose to come here instead. But they kept making faces at me while I was making my speech."

Georgia was on crutches after twisting her ankle in a fall from her climbing frame.

The couple with children Georgia and Elizabeth

After touring the new centre, built with the help of a �1.7m National Lottery grant, he posed with members of a school band who had played a version of the Stones' Brown Sugar - and joked that he might return to stage a concert himself.

Jagger helped make up the rest of the cost of the �2.25m centre, which features two fully-equipped, flexible venues, a recording and video studio, rehearsal rooms, a bar and a gallery. It was officially opened with the unveiling of a plaque by the Duke of Kent.

Standing in the centre, Jagger said: "This used to be the school assembly hell, where each morning we would sing our hymns and either be praised or damned for our behaviour."

Jagger helped fund the new centre

He recently told a newspaper how he had not enjoyed his school days, and told the audience: "I hope I didn't give an impression with an interview with The Times a few days ago that this school was a mixture of Blackboard Jungle, Dotheboys Hall and St Trinians."

The audience dissolved into laughter, and he joked: "I did? I went over the top?"

Jagger had told the paper how he had organised a revolt against the school's dinners, and how teachers each had their "own tortures".

He went on to tell the audience: "There are shatterproof windows in the new block to prevent damage from footballs, there are salads and chips for lunch, and tweaked ears by maths masters are instantly reported to Childline."

The best days of his life? Mick Jagger in the school's 1960-61 basketball team

After the school band had finished their performance, Jagger signed their guitars, before writing on the wall of the centre's studio: "I was back! Mick Jagger."

The facilities are open to the local community as well as the school's pupils, and the scheme's backers hope it will boost the cultural life of the town, on the outskirts of London, where Jagger was born in 1943.

He left school in 1961 with seven O-levels and two A-levels, and went on to study at the London School of Economics, founding the Stones with childhood friend Keith Richards a year later.