British Transport Police (BTP) officers have issued two CCTV pictures in an effort to find a man following a sexual assault on a sleeping woman onboard a train in Surrey.
In the early hours of Sunday 14 December, the 25-year-old woman was travelling between London Victoria and Merstham when the incident happened.
Detective Constable Helen Magill said: "The victim was sitting next to a man on the train as it headed out of London.
"She spoke to the man, before falling asleep. A short time later, the woman woke to find the man kissing and touching her inappropriately.
"The victim stood up quickly and moved to another seat.
"Do you know the man in the photos we have released today? This was a Saturday night-Sunday morning, 11 days before Christmas. Perhaps you were on that train, the 12.14am from London Victoria to Three Bridges.
"If you saw what happened, or recognise the man in either of the two CCTV images, please contact BTP."
Anyone with information on this incident should contact British Transport Police, on 0800 405040, quoting reference SSUB/B3 of 17 February 2015. You can also text BTP, on 61016. Information can be passed to independent Crimestoppers, on 0800 555111.
The UK's worst train stations
Woman falls asleep on train and wakes up to man sexually assaulting her
This Edwardian station was built in the early 1900s and is operated by East Midlands Trains. 59 per cent of people surveyed said they were satisfied with the station - a low score which ranked it bottom for both cleanliness and facilities in the Passenger Focus National Passenger survey.
Birmingham New Street railway station is the largest and busiest serving Birmingham. Despite the regular flow of people, only 64% of passengers surveyed in the National Rail Passenger Survey (NRPS) are satisfied with the sation.
London Bridge railway station is a central London railway station and a London Underground complex in the London Borough of Southwark. The station is the oldest railway station in central London and one of the oldest in the world. 67% of passengers surveyed were satisfied with this station, the fourth busiest station in London.
Peterborough railway station is a major interchange serving both the north-south ECML, as well as East-West long-distance and local services. The station is managed by East Coast. Just 67% of passengers surveyed were satisfied with this station.
Crewe station was completed in 1837 and is one of the most historic railway stations in the world. Like London Bridge and Peterborough, only 67% of passengeres surveyed were happy with this station.
Gatwick Airport station provides a direct rail connection to London. The station platforms are located about 70 metres away from the airport's South Terminal. 69% of passengers surveyed were satisfied with this station.
Stockport railway station was identified as one of the ten worst category B interchange stations by a mystery shopper assessment in 2009. Despite improvements being made to the station since, it is still one of the ten worst stations with only 70% of passengers satisfied with the station.
Clapham Junction station is one of the busiest in Europe by number of trains using it with many routes from London's two busiest termini, London Waterloo and London Victoria. Only 71% of passengers surveyed were satisfied with this busy station.
Maidenhead railway station serves the town of Maidenhead, Berkshire, England. It is served by local services operated by First Great Western from London Paddington to Reading, and is also the junction for the Marlow Branch Line. The survey showed 71 per cent of respondents were satisfied with the overall quality of the station, giving it the ninth lowest satisfaction rating.
Coventry station has the PlusBus scheme where train and bus tickets can be bought together at a saving. Despite this convenient feature, only 72% of passengers surveyed were satisfied with the station.