Sotheby's declare 'Frans Hals' work a forgery

A work thought to be by Dutch artist Frans Hals that sold for a reported £8.5m in 2011 has been declared a fake, the BBC reports.

Sotheby's said it had "rescinded the sale and reimbursed the client in full" after tests revealed the painting, An Unknown Man, was "undoubtedly" forged.

The investigation followed reports that a sophisticated forger is at large.

The forger is also believed responsible for a painting attributed to Italian master Orazio Gentileschi that was loaned to the National Gallery.

The painting, David Contemplating the Head of Goliath, was loaned to the gallery by its current owner in 2013 and was on display until March this year. It has since been returned.

The National Gallery said it "undertakes due diligence research on a work coming on loan as well as a condition check", and that these were carried out on the painting.

'Modern materials'

Another disputed work, attributed to Renaissance artist Lucas Cranach the Elder, was seized by authorities in France in March after doubts were raised about its authenticity.

The work had been loaned to an exhibition in Aix-en-Provence by Hans-Adam II, the reigning Prince of Liechtenstein.

According to The Art Newspaper, the work came on to the market in 2012 and was sold "in good faith" to the prince in 2013.