A British musician who launched a public appeal after leaving his 310-year-old violin on a train was reunited with the undamaged instrument in a secretive meeting in a supermarket car park.

Police told AFP on Monday there would be no further action taken against the man who returned the violin, which is reportedly worth around €290,000.

Mr Norris, reunited with his instrument. Photo: Twitter/@stephen55649619

"My violin is home safe and sound! Thanks for the overwhelming support," the musician, Stephen Norris, tweeted at the weekend.

He had left the violin, which was made by Roman master craftsman David Tecchler in 1709, on a commuter train out of London last Tuesday.

British Transport Police issued an image of the man believed to have taken it, and Morris received a message on social media from someone claiming to have information.

According to the BBC, the man called himself "Gene" and arranged to meet Morris in a supermarket car park on Friday evening, where he handed over the violin in a bag.

"He was very apologetic, he said he wanted to hand it to me in person," the musician said, adding that the violin and bows were intact.

A British Transport Police spokesman told AFP the violin had been returned, and said no further action was being taken against the man who had it.