A portrait depicting the British actor Robbie Coltrane is to go under the hammer at Sotheby's in London for £50,000 to £70,000 on September 30.

The portrait, entitled Blind Leading the Blind III, by Peter Howson depicts the artist's friend Coltrane leaning over a barrel.

Viewing to the public starts in Edinburgh from 15-17 of this month before heading down to London.

BAFTA winner Coltrane is currently filming the forthcoming Harry Potter and the Deathly Hallows.