The House flag of Cairn Line of Steamships Ltd, Newcastle-on-Tyne. A rectangular flag divided into quarters of blue and white. A rope and toggle is attached. The flag is made of a wool and synthetic fibre bunting. It has a cotton hoist and is machine sewn.

In the early years of the 20th century, the Cairn's cargo steamers used a red House flag with a white pyramid in the centre (a pun on Cairn) with the letters 'CY' in black (the initials of Cairns & Young). In 1907 they purchased William Thomson & Sons and used both the Cairn flag without the lettering and William Thomson's blue and white chequered flag — itself taken over from an earlier shipping firm owned by the Norrie family. After the takeover of the Cairn Line of Steamships by Furness Withy in 1928, the company operated under the blue and white flag, although the white triangle was retained as a funnel insignia.