Brighton-based artist Charlie Schaffer has been named the winner of this year's £35,000 BP Portrait Award.
He took first prize for his portrait Imara In Her Winter Coat, a painting of his close friend wearing a fake fur coat.
But the award has been overshadowed somewhat by a row over BP's continued sponsorship of the prize.
Before the ceremony on Monday, judge Gary Hume said the company's involvement "was now a problem".
Performance activists blocked entrances to the event at the National Portrait Gallery, preventing guests from entering for about half an hour, according to protest group BP or not BP?
Eight artists who have previously won or been shortlisted for the prize have also voiced their disapproval of BP's association in a letter to National Portrait Gallery director Nicholas Cullinan.
As the winner, Schaffer received £35,000 prize money plus a commission from the National Portrait Gallery worth £7,000.
The judges said the winning portrait had "a strong sense of a living presence".
They added: "The skilful depiction of a combination of several different textures including faux-fur, hair and skin are revealed by prolonged looking and together these produce an image that is traditional, but clearly contemporary."
The second prize of £12,000 went to Norwegian painter Carl-Martin Sandvold for The Crown, a self-portrait.
The third prize of £10,000 went to Italian artist Massimiliano Pironti for Quo Vadis?, a painting of his maternal grandmother Vincenza, a former miller and factory worker now aged 95.
All three of this year's winning portraits along with selected other submissions will be on display at the National Portrait Gallery from Thursday.
Climate change campaign group Extinction Rebellion is planning a protest in Trafalgar Square at 17:00 BST on Tuesday before one of the Royal Opera House's open-air summer screenings, which are also sponsored by BP.