Procuress (after Dirck van Baburen)

This copy of a 1622 brothel scene by Dirck van Baburen has a strange double life. Baburen's original once hung in the house of Vermeer's mother-in-law and appears in the background of two genuine Vermeers, so it sits at the heart of the Delft world Han van Meegeren spent his life faking. The Courtauld received this version in London in 1960 as a known van Meegeren forgery. Then doubt crept in, and by 2009 a study suggested it might be a real 17th-century copy after all. In 2011 a television investigation had the paint analysed and found phenol formaldehyde, an early plastic patented in 1909, worked into it, along with an older scraped-off composition underneath. That settled it. The gallery catalogues the picture today as van Meegeren, after Baburen, painted around 1930.