It remains one of TV’s rarest achievements, but Who Wants to Be a Millionaire? has crowned its seventh £1m-winning contestant, bringing a six-year drought to an end. Retired IT analyst Roman Dubowski was the lucky individual who answered all of his 15 questions correctly to win the jackpot. Throughout his time in the hot seat, he had one near miss at the £1,000 mark, when he was asked the missing key ingredient in mayonnaise. But he whizzed through the remaining questions put to him by host Jeremy Clarkson , who branded him “an encyclopaedia in a shirt”. Roman Dubowski wins 'Who Wants to Be a Millionaire? jackpot (ITV) He was left with two lifelines for the final question, including 50:50 and Ask Jeremy, in which contestants can ask Clarkson for his input. After winning the cash prize, Dubowski, who had unsuccessfully applied twice before to get on the show, said: “I thought I was good enough to win, say, a five-figure sum because I’ve seen the show so much.…