Fake or Fortune?

Fiona Bruce and Philip Mould investigate more potentially valuable works of art. They begin with an 18th-century landscape that could be a lost work by of one of the biggest names in British art, Thomas Gainsborough. The painting has been in the family of owner Mark Cropper for generations and until the 1970s it was considered to be a Gainsborough. But then a valuation downgraded it and Mark's father tore off the Gainsborough label in disgust. Now Mark would love to be able to re-apply the Gainsborough plaque.

Can the team prove that a portrait attributed to pioneering female artist Maria Cosway is actually an undiscovered work of the great Regency artist Sir Thomas Lawrence?

Bought for just £1, could a small still life be the work of one of the masters of early 20th-century art, Giorgio de Chirico?

Fiona Bruce and Philip Mould investigate the provenance of a painting with a Venetian view, trying to ascertain whether it is the work of Francesco Guardi or Michele Marieschi. Owner Nick Hopkinson inherited the painting from his great grandfather and Guardi and Marieschi are both known for their depictions of Venetian views and were contemporaries in the 18th century of Canaletto. But there's a big difference in value between them - if Nick's painting is a Marieschi it could be worth half a million pounds, if it's a Guardi it could be worth up to £10million.