The amnesty is part of an operation by Thames Valley Police to cut the number of false alarms and serious crimes involving fake weapons or ball-bearing guns.

The force says replica guns can be extremely difficult to distinguish from real weapons - yet all crimes that are reported to involve guns have to be treated as real firearm incidents.

This often wastes valuable police resources if the gun later turns out to be fake.

'Terrifying threat'

Although imitation guns are not illegal, a police spokesman said: "Being threatened with a replica gun is just as terrifying as being threatened with a real gun, and is treated very seriously in the courts with sentences of up to 10 years."

I was horrified at first that in this instance vouchers are being given out, but maybe we have got to try another tactic

Linda Mitchell, Campaign For Air Gun Control

Over the past year, 37 replica and ball-bearing guns were recovered by Thames Valley officers.

Children are being offered �10 vouchers to spend in a music store if they hand in the guns between 18 November and 8 December.

Parents are also being urged not to buy replica guns as Christmas presents.

'New tactic'

Linda Mitchell of the Campaign For Air Gun Control said she was sceptical at first of whether the scheme would have any significant impact.

She said: "During the various amnesties that police forces have held in the past, the amounts of air guns and ball-bearing guns they get in are minimal.

"I was horrified at first that in this instance vouchers are being given out, but maybe we have got to try another tactic to try to get children to give up the guns before they injure someone with them.

"We haven't got anyway of knowing how many air guns or ball-bearing guns are out there so I guess this is worth trying - whether it is a success remains to be seen."