Three teenage boys were robbed in what police have called a "nasty, unprovoked" attack last week.

The three boys, all 16, were in Watercress park, Hackbridge, when two men approached them and said they had a knife shortly before 10pm on Friday, May 17.

One of the victims was attacked, leaving him with swelling and bruising to his cheek and forehead.

The robbers stole the teens' wallets and mobile phones.

Detective Constable Natalie Laing from Sutton police said: "This was a nasty, unprovoked robbery on a group of boys walking in the park."

The suspects are two men, thought to be in their late teens.

One was black and the other was white and both were riding bicycles.

They left toward the Spencer Road exit from the park.

If you have information you can call Sutton CID on 020 8649 0747 or the charity Crimestoppers on 0800 555 111.