Although at least two portrait drawings by his father were exhibited in Dirk’s lifetime, it is thought that he sat only once for an official study. This was commissioned by the National Portrait Gallery in 1986 from the Royal Academician David Tindle, who spent four days with Dirk at Clermont. The finished painting, in tempera on canvas, hung at the NPG and was one of four works lent temporarily to No 10 Downing Street shortly after Tony Blair became Prime Minister.
A preliminary drawing in pencil was exhibited at the 1988 Royal Academy Summer Exhibition. In late 2006 the artist released from his studio a pre-study, which was shown by the Redfern Gallery at the annual Art London fair in Chelsea. It carried a price tag of £30,000.