A man with learning difficulties was punched and elbowed in the head on a train after telling his shirtless attacker that the toilets were out of the order.

The victim, aged 37, was returning from a day out with friends on June 6 when he was assaulted.

He boarded a train travelling from Surbiton to Waterloo about 10.30pm, when an unknown man, who was wearing Hawaiian shorts and no top, approached him.

The victim told the man that the nearby toilet was out of order, and the man responded by punching him several times in the face and elbowing him in the head.

The assailant got off the train at Clapham Junction Station, and the victim left at the same station, where emergency services were called and he was treated for a cut to his eye.

PC Dan Rolfe, from British Transport Police (BTP), said: "This was a cowardly attack that appears to be motiveless.”

Police have released a CCTV image of the shirtless attacker.

He was 25 to 35 years old, about 5ft 10in, with short brown hair.

He was wearing white and blue Hawaiian-style shorts and no shirt, but was carrying a dark coloured t-shirt.

Anyone who can identify the man should call BTP on 0800 40 50 40 or the witness appeal line on 020 7391 5275.