A schoolboy is in shock after being stripped naked and forced to "walk the plank" into the sea by three bullies in Worthing.

The attack traumatised the 15-year-old victim who was left trying to cover himself with just a sock after his tormentors ran off with most of his clothes.

A police spokeswoman said: "This young man is still in shock and suffering after this assault. He was put through a terrible ordeal."

The teenager was approached by the youths at a stretch of beach opposite Brooklands Park in Worthing and told they would beat him up if he looked at them.

During a 20-minute ordeal, they made him walk out to sea along a sewer outlet pipe, continually pushed him in to the water and robbed all his clothes.

The humiliating attack has left the schoolboy too scared to speak out.

He was first threatened at 7.30pm, on Monday, when one of the bullies told him to go down a pipe leading out to sea. He then pushed him off it.

The orders were repeated three more times but on the fourth attempt the soaking teenager slipped, banging his forehead and knees on the pipe.

The impact caused bruising and a cut to his right hand.

The spokeswoman said: "The offenders told the victim to lie down and sit in the sea, which he did, swallowing sea water in the process.

"They then started to make him take his clothes off on the shore. The victim had removed his top when a woman walking her two dogs approached and asked if everything was okay.

"The offenders stated the victim had fallen off the pipe. After the woman had gone, the offenders then continued to threaten the victim and he complied with their requests fearing for his safety.

"He removed all of his clothes and was left naked on the beach while the males put his clothes on the north side of the A259 which runs parallel to the sea.

"The victim managed to cover himself up with a sock, which the males dropped and a man came to the his assistance and gave him his clothes back, which he quickly put on as he was very cold, frightened and in shock."

Police are appealing for witnesses to contact them on 0845 6070999.