A man is being sought by police over the theft of a 310-year-old violin worth £250,000 which was taken from a train.
Musician Stephen Morris was on the London to Orpington service on 22 October when he got out at Penge East with his bike but forgot the violin.
It was one of only a few made by master craftsman David Tecchler in 1709.
British Transport Police have released a CCTV image of a man they want to speak to.
The force said that, as the Southeastern train approached Bromley South "another man took the violin and left the train".
The man is said to have boarded a connecting train to St Mary Cray.
Mr Morris was on the 22:58 London Victoria to Orpington service when he lost the antique instrument.
He had been due to play the violin while leading the Royal Philharmonic Orchestra in two Andrea Boccelli concerts on the weekend.
The musician, who has also played on film scores including The Lord of the Rings and James Bond and recorded with David Bowie and Stevie Wonder, reported it to lost luggage and the police.
Mr Morris has urged anyone who finds the violin, which he bought in 2003 and described as "a piece of history", to "please return it".
"It's devastating to lose it and quite apart from its value, it's my livelihood," he said.
"I was really only its custodian - one of many people who have played it - and I had hoped to pass it on to another violinist eventually."
Mr Morris, from Sydenham in London, had to borrow another violin from his wife, who is also a professional musician, for performances in Manchester and Leeds on the weekend.
"According to my colleagues playing this other violin hasn't affected my performance, but it was like having my arm cut off," he said.
"The way my instrument responds is like having a limb - your hand and brain know exactly where to go when playing."
Tecchler was part of the renowned Roman School of Violin Making in the 17th Century and was considered to be the institution's leading violin and cello maker.
The instrument, which is marked with Tecchler's name, had recently been restored and was in a white case when it was left on the train.