Officers are scouring the area around Trent Close for the male suspect.

He is described as aged in his 20s, white, six feet tall, with dark wavy hair.

He struck near Trent Close, not far from Waterfield School, just after 11am today (Thursday June 25).

His female victim was crossing a footbridge over a stream.

A Crawley Police spokesman confirmed the man pulled down his trousers and performed a sex act on himself.

The spokesman added: "We need help in an appeal for information. It follows an incident at 11am this morning in Bewbush. A woman was crossing a footbridge when a man approached her and dropped his trousers.

"Ground units are in the area searching for the suspect.

"Obviously we're very keen to find this man."

Any information to Crawley Police on 0845 60 70 999.

If you see the man contact the newsdesk on 01293 845055.