A "vital" witness could hold the key to an investigation into the secual assault of a 16-year-old girl.

The girl was grabbed by a man as she walked along Malthouse Road, Crawley, on Monday morning.

The witness shouted at the man, who was white, scruffy and bearded, to "get off her" after the man grabbed her arm and sexually touched her over her clothes as she walked to the train station.

If you're the man who came to the girl's aid or if you have information please contact police on 101, email 101@sussexn.pnn.police.uk or call the independent charity Crimestoppers anonymously on 0800 555 111