POLICE have released an image of someone they want to speak to after a man exposed himself to a group of primary school children on a train.

The man also touched himself inappropriately while staring directly at the children, in what police described as a 'disturbing incident'.

It happened on the 2.05pm train from Aylesbury to Marylebone on Tuesday, June 10, with details emerging this week as pupils did not make teachers aware of what happened at the time.

The children got on the train at Aylesbury with some of their teachers and exited at Amersham. The man, who also got on at Aylesbury, stayed on board the train.

As part of their investigation detectives from British Transport Police viewed CCTV from the train, and have spoken to potential witnesses at Aylesbury and Amersham stations.

DC Martin Coulstock, who is leading the investigation, said: "This is a disturbing incident, and the children involved were confused and upset by what happened.

"We need to find the person responsible. I am confident that the man in the images we are issuing today can help with our investigation.

"If anyone recognises him, I would urge them to contact us."

Anyone with information should contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference ESUB/B3 of 26/08/2014.

Information can also be passed anonymously to the independent charity Crimestoppers on 0800 555 111.