Three 16-year-old girls were in the Cuttlebrook Nature Reserve on Saturday night when they were approached by two men.

The incident took place at about 9.30pm on Saturday night in the reserve, which is the land next to the Southern Road recreation ground.

Police say the offender is in his early 20s white and about 5ft 9ins.

He has broad shoulders and well built arms with a fat waste.

His hair was short, light brown which was jelled into spikes.

The other man is whiet, about 6ft, and was slimmer than the other man and had dark jelled hair.

Det Sgt Alan Clements, investigating the incident, said: "We are urging the public to help us trace these men.

"I appeal to anyone who may have been in the park on Saturday evening to contact us as it was a nice, warm evening and there were plenty of people around at the time."

Anyone with any information about this incident is asked to contact Det Sgt Alan Clements at Thame police station via 0845 8 505 505, or if you do not want to talk to the police or give your name, call the Crimestoppers charity on 0800 555 111.