A man was put in a headlock and punched in the face several times while two phone thieves tried to steal his phone on the Tube in West London, British Transport Police said.
Two men attacked the passenger around 10.50pm on Monday August 26 on a Central Line train between Shepherds Bush and White City stations.
British Transport Police has released CCTV images of two men in connection to the assault.
Officers believe the men in the CCTV images may have information that could help their investigation.