The painting is known as “Arab in Black” – and was painted in 1939 by South Africas’ leading artist, Irma Stern.  It was once sold to help fund Nelson Mandelas’ legal defence.

Hannah O’Leary, a specialist in South African art at Bonhams auction house, spotted the painting during a valuation visit to the flat.  Hannah told the Guardian : “I spotted this masterpiece hanging in the kitchen covered in letters, postcards and bills. It was a hugely exciting find, even before I learned of its political significance”.

Irma Stern passed away in 1966, and her old home in Cape Town is now a museum.  There has been a healthy interest in her works, with prices rising steadily over time.  Another of her paintings of subjects from Zanzibar, similarly framed in heavy, antique, carved timber, set a new world record at Bonhams in 2011 when it sold for £3.1m.

In the late 50s, the collector Betty Suzman gave the painting to a charity auction to raise funds for Nelson Mandela and other African National Congress activists, who were on trial for high treason.  The case was dismissed after lasting five years, but Mandela, and others were re-arrested a further three years later and given life sentences for treason. Mandela was eventually freed in 1990, and went on to become his country’s president.

To add further to the uniqueness of the piece, the frame is made from timbers of antique door cases from Zanzibar, which are now barred from export.  Irma Stern had spent several periods working in Zanzibar in the 1930s and 40s, and used the frames for what she considered her best works.  The parents of the present owner moved to the UK in the 70s, which is how Irmas’ million pound artwork ended up here as a noticeboard.

“The words ‘shocked’ and ‘astonished’ would both apply to the present owners,” Giles Peppiatt of Bonhams told the Guardian. “They loved the painting and they knew it had some value, but they had no idea it was such an important work. In some ways they are very sorry to see it go, but it would be a great luxury to keep a million-pound painting hanging on a kitchen wall.”
The painting will be sold at the Bonham’s auction of South African Art in London on 9 September.