A schoolboy has been suspended after a £3 ball-bearing gun he bought at a Sunday market was used to shoot a classmate.

The girl was not seriously injured by the plastic pellet, which hit her in the hand but campaigners today called for a clampdown on the sale of such weapons.

Jamie King, 13, of Horsham Close, Whitehawk, took the gun into Longhill School in Rottingdean on Monday to show his friends.

He told his teachers he and a group of friends were playing with the weapon when one of them fired it, injuring the girl.

Jamie bought the gun on Sunday at Ford Open Market on Ford Airfield, near Littlehampton.

Lesley Cope, 37, Jamie's mother, said: "At the market he went off on his own and the trader has just handed it over to him.

"If the police can have a knife amnesty I think they should have a BB-gun amnesty as well."

The market has a ban on weapon sales and site manager Gary Brown said any trader caught selling them would be kicked out of the market. Arun Police work closely with the market authorities to keep checks on what is bought and sold there.

Mr Brown said: "They all know the rules, in no uncertain terms."

Jamie said the trader had not asked him his age before selling him the gun. He said there had been a larger model also on sale for £5.

He said: "Lots of my mates have them and I wanted one just to show them I had it.

"I had heard about the metal ball-bearing ones being dangerous but not the plastic ones.

"I would tell people not to go and buy BB guns."

The school has handed the gun over to police and deputy headteacher Jonathan Sargent said staff would speak to pupils about the dangers of BB guns.

Mr Sargent said: "It was a foolish schoolboy act. It's an entirely inappropriate item for a child to have and gun culture is not something we condone."

There is no law against selling BB guns to children.

Brighton and Hove City Council cracked down on BB gun sales after a rising number of incidents, including a shooting in 2004 when nine-year-old Levi Pettit suffered a serious eye injury.

They put pressure on the organisers of the bank holiday markets at Brighton racecourse to ban under-the-counter sales of the weapons, which resulted in dozens being seized.

Campaigner Maggie Smeeth, of Whitehawk, said: "We have been trying to get them banned altogether and we think it should be a nationwide thing. They are so dangerous."

A Sussex Police spokeswoman said BB guns could be impossible to tell from the real thing so anyone carrying a replica weapon could find themselves confronted by armed police officers.