A gang of "hoodies" who robbed a teenager at last year's National Action Sports Show at the Bath and Wells Showground, near Shepton Mallet, have been sentenced.

Marcell Richards, 19, of Harringay, London, and two youths aged 17 and 16 grabbed their young victim from behind while he was watching music at the show in July last year.

Wearing their hoods up over their heads, they held his arms and went through his pockets, taking his wallet and other articles, Taunton Crown Court was told. About 30 minutes earlier, a 15-year-old boy was grabbed and put in a headlock while his pockets were searched and a mobile phone was taken.

All three admitted two offences of  robbery and possessing cannabis and Richards also pleaded guilty to theft of a mobile phone.

One of the defendants, a boy from Stroud, had two previous court appearances while the others had clean records, said Martin Lanchester, prosecuting.

The 17-year-old defendant was said to have been offered a place by three universities and the offences were completely out of character.

He was described as a young man with a very clear idea of where he wants to go in life.

Judge Graham Hume Jones said people were very concerned about gangs of young men bullying others and why the three of them with relatively-good characters set about doing so he could not understand.

Because of their past records, they were not going to prison but "if it happens again you will go inside and there's no question about it".

"I am taking a course which I hope will assist you in your lives so you won't go on committing offences and appear in court again," he said.

The 16-year-old was given two years supervision, and the older youths were sentenced to a 12-month community order with 150 hours unpaid work and a three-month curfew with electronic tagging.