Rare Titanic poster found hidden behind wall

Be careful when you're renovating your home: there could be hidden treasure to find.

A poster advertising the Titanic has been found by a couple doing up their home, and is now up for auction with a guide price of £2,000 to £3,000.

Designed by leading marine artist, Montague Birrel Black, the lithographic print measures 23 inches by 36 and was produced in 1910 or 1911.

"This exceptional image is the most iconic example of White Star Line promotional imagery for the Titanic and would have been used in travel agents and White Star Line offices to advertise the Titanic and Olympic," say Wiltshire auctioneers Henry Aldridge and Son.

"After the Titanic disaster their posters were withdrawn from service and destroyed which explains why there are only a handful in existence today."

According to the Daily Mail, the unnamed couple demolished a partition wall in their Victorian house in Wales and found a landscape painting hidden in the cavity behind.

While they liked the frame, the painting wasn't to their taste; and when they removed it, they discovered the poster underneath. The edges are frayed and it's missing the agent's section, which would have been at the bottom, but the imagery itself is intact.

"I have come across people finding treasures in the attic but not behind a false wall," says Andrew Aldridge, of Henry Aldridge and Son.

Titanic memorabilia is big business. Last autumn, a lunch menu from the ship's final voyage was sold for $88,000, $18,000 more than the pre-sale estimate.

Other items in September's auction include the first letter written on board the ship, from author Paul Danby. He was visiting a friend on board, and wrote to his wife, describing the interior of the ship.

"This letter is exceptional for several reasons, but principally due to the author writing that it is the first to be sent from on board," say the auctioneers.

"Paul would only have been on the Titanic for a short period, but he took the time to write this letter."

The lot, which also includes original photos of Paul, his wife Rose and the uncle he was visiting on bard, is expected to sell for £10,000 to £15,000.