A son of late painter Lucian Freud has launched a legal battle to claim a share of his father's multi-million dollar fortune.

Freud, most famous for the painting nicknamed Big Sue, passed away in 2011 aged 88, after battling a mystery illness.

He left $4 million (£2.5 million) and his London house to his assistant David Dawson, and his remaining $67.2 million (£42 million) fortune was put in a trust fund, managed by solicitor Diana Rawstron and Freud's daughter Rose Pearce.

Freud's other 13 children were not left any inheritance and both trustees have refused to reveal if the painter left instructions about how the fortune should be shared.

Now one of the artist's sons, Paul Freud, 55, is challenging the legality of the trust fund at the High Court in London, claiming his father may not have left any instructions to the trustees because the fortune was never subject to a will, according to British newspaper The Daily Telegraph.

Paul is one of four children from Freud's relationship with art student Katherine MCAdam.