Ball bearing guns look realistic and are cheap to buy

Officers warn that because the so-called "BB Guns" look realistic, incidents often lead to armed police being called.

Lancashire Police are visiting schools in the Lancaster area, where a number of cases have been reported.

Armed response unit officers have warned pupils the incidents could lead to tragic consequences.

PC Matt Sanders - of the Lancaster-based armed unit - told BBC Radio Lancashire: "The worst that can happen is that we can make a mistake.

'Families' loss'

"We could unfortunately shoot somebody who's armed with only a replica or a toy BB gun."

He said officers would then face criminal proceedings, and possibly jail.

"We would also have the knowledge that we had shot somebody which would be a loss for the families involved and for our families," added Mr Sanders.

Problems are made worse by the fact the BB guns are available for as little as �1, he said.