Just days before the Epsom Derby, police have issued a fresh appeal for information about an unsolved sex attack on a 15-year-old schoolgirl at last year's race.

A second girl, also 15, received minor cuts and bruises after another teenager took her to the same place in woodland near the fairground and music area at Epsom Downs Racecourse.

Police are appealing for racegoers this year to assist in the hunt for the pair who put victims through a ‘horrendous ordeal’ on Saturday, June 2, 2012.

Crimestoppers are offering up to £3,000 as a reward for any information which leads to the arrest and conviction of the teenager who carried out the sexual assault.

The teenage boy, aged between 16 and 17, met the girl on the day and carried out the assault at about 4pm.

The skinny teenager, with muscular build, is described as having a prominent wide jaw, short gingery blonde hair and pale, spotty skin.

On the day of the sexual assault, he was wearing a dark blue top with long sleeves and baggy blue jeans.

Earlier in the day he was accompanied by another teenager of a similar age who had a larger build and short flattened brown hair.

This youth is believed to have inflicted minor cuts and bruises on the second teenage girl.

He was tanned and wore a white top and blue baggy jeans.

Officers will speak to racegoers during Ladies Day on Friday and the main event on Saturday in a bid to help solve the case.

Detective Constable Ian Cherrington appealed for anyone with suspicions around someone they know to speak to police in strictest confidence.

He said: "The Epsom Derby is visited by a large amount of people from all over the country so we are using the event this year to speak to those that visit annually who may have information to solve this case.

"Since the offence last year we have been working closely with the families and supporting the victims through what was a horrendous ordeal for them and urge anyone who can us help bring the offender to justice to come forward."

Anyone with information should call police on 101, quoting reference EP/12/2172, or Crimestoppers anonymously on 0800 555 111.