AIR Force Top Guns have already battled UFOs in the skies over Britain under a top-secret Government directive, a former senior insider has sensationally claimed. Nick Pope - whose 21-year stint at the Ministry of Defence included three years on the UFO desk - told The Sun of the rules of engagement for the first time. He claimed RAF pilots had fired at UFOs several times - but couldn't take them out.And he added: "We know of cases where the order has been given to shoot down - with little effect to the UFO."