British Transport police are urging paasengers to report sexual incidents after a woman said she was targeted by a flasher on the Docklands Light Railway.

The incident, which occurred on January 29, has not been reported to officers but it is understood that a man exposed himself to a woman as she was travelling to Stratford on a packed train between 5.45pm and 6pm.

The man was described as “Asian looking, in his 40s, dressed casual in jeans and a fleece and unshaven.”

Detective Sergeant Sandra Webb, of British Transport Police’s Public Protection Unit, said: “While this type of offence is extremely rare on the Dockland Light Railway and London Underground, we know that it can be an extremely upsetting and intimidating experience for anyone who is a victim. We take sexual assaults very seriously and do everything we can to identify and arrest those responsible.

“We know that victims of unwanted sexual behaviour often don’t report it to police, either because they don’t think it was important enough or they are not sure that it happened. I urge anyone who suspects they have been a victim of an offence like this to report it to police so that it can be properly investigated.

“Reporting the offence is crucial as it helps my team of detectives to build a picture of an offender’s behaviour and establish their pattern of travel across the network. We can then increase police patrols and secure CCTV evidence, increasing the likelihood of an arrest and conviction.”

If you have been a victim of a sexual offence on the London Underground, DLR or rail network, or see someone acting suspiciously, call British Transport Police on Freefone 0800 40 50 40. In an emergency, always dial 999