A commuter had to be taken to hospital after a boxer dog attacked him on the tube, biting him so hard he left three puncture marks in his crotch, police said.
The 55-year-old man was attacked on a Piccadilly line train at Ealing Common after he attempted to sit opposite a man with a Rottweiler and a boxer-cross.
British Transport Police are now searching for the owner of the dogs, who is described as being black, around 35-40, with an afro. He had a green comb sticking out of his hair, police added.
The appealed for any witnesses who were there at the time of the attack, which happened on Monday, May 20 at 6.30pm.
A spokesperson for London Ambulance said: "We were called on May 20 at 7pm to reports of a man bitten by a dog at Royal Park station. We sent one ambulance to the scene where staff treated a patient before taking him to the Central Middlesex Hospital."
It isn't the first time a man has been attacked by a dog at a tube station. A man was left with injuries needing plastic surgery after a pitbull terrier savaged a man's face at Hammersmith Tube station in January.
More recently a 79-year-old man was mauled to death in Liverpool. The breed of dog has not been confirmed but it was said by people in the area to have resembled a Staffordshire Bull Terrier. Two women have been arrested.