A West Sussex teenager was robbed at knifepoint as he walked home from his birthday celebrations.

The 17-year-old had left the beach in the early hours of yesterday.

He was walking with friends along Parkside Avenue, Littlehampton, at about 1am when a group of four youths called out asking them to wait.

They forced the teenager to the ground and one produced a 3in knife.

The gang stole the boy's Adidas rucksack, containing a phone, wallet, clothes and cigarettes, before running off down Leeward Road into the housing estate.

Police said the boy suffered scrapes to his elbow and knuckles. All the offenders wore hooded tracksuit tops.

The youth carrying the knife is described as black and more than 6ft tall. Two others were in their late teens. There is no description of the fourth.

A police spokesman said: "It was a distressing end to a birthday celebration."

Anyone with information can contact Sergeant Matt Liau on 0845 6070999.