Anita Singh, arts and entertainment editor. Hyperallergic. It was rumoured to be the world’s most expensive painting, a Gauguin masterpiece bought by the Qatari royal family in a deal that had the art world agog. Now a High Court battle has revealed the secret dealings behind the sale, as a broker known as “the Mick Jagger of … More Gauguin masterpiece dubbed ‘the world’s most expensive painting’ at centre of High Court battle