Some young children in Britain are being indoctrinated to hate non-Muslims and champion a holy war, according to a new documentary.

"No child is ever too young to be started off on Jihad training," states one document recovered by police from the North West's Counter Terrorist Unit (CTU) during raids.

CTU officers, interviewed by the BBC's Inside Out team for a special programme, show the document and a film they recovered of two children aged about three and six playing with a pistol and Kalashnikov rifle.

The officers say the discoveries are evidence of attempts to radicalise youngsters. The footage, which police believe was filmed in Pakistan, was uncovered on the hard drive of a suspect's computer – though investigators have not revealed when the material was seized.

The video shows a girl and young boy playing with guns, which police believe are real. "What do you do with the weapon?" asks a man's voice. He answers his own question: "I want to kill the infidels."