Police have issued warnings after a spate of clown sightings across the UK , mimicking a prank that began in the US and has spread across the world. Police forces said they had received dozens of reports of "killer clown" sightings in the last week in which individuals dressed in clown outfits, sometimes carrying knives, have acted suspiciously or chased people, often young children."We believe this to be part of a larger prank that is currently sweeping across the US and parts of the UK," said Sergeant Mel Sutherland of Durham Police.The recent craze led best-selling US horror author Stephen King, whose 1986 novel It tells the story of a supernatural being that appears as a clown, to appeal for anti-clown sentiment to be tempered."Hey, guys, time to cool the clown hysteria - most of 'em are good, cheer up the kiddies, make people laugh," King wrote on his Twitter website last week. ..