A painting by the British street artist Banksy sold for a record £16.75 million ($23.1 million, 19.4 million euros) on Tuesday, with proceeds going to the state-run health service. The painting, "Game Changer", sold for £14.4 million plus costs -- the highest ever for a Banksy painting -- after fierce competition between bidders in a nail-biting sale at Christie's auction house in London. am/phz/jv