Models, pictures and memorabilia of two very different Britannias have gone on display at the Queen's Norfolk retreat.

The Royal Yacht Britannia carried the Queen and members of the Royal Family on tours around the globe from 1954 until she was formally decommissioned in 1997.

She had a sleeker namesake who was a racing yacht built for speed.

Built for King Edward VII, in 1893, she was inherited by King George V after Edward died, in 1910.

He enjoyed sailing and racing her, and when he died in 1936, she was sunk off the Isle of Wight, in accordance with his wishes. Her fine fittings were removed beforehand and auctioned to raise funds for King George's Fund for Sailors (now Seafarers UK). Her wheel was later installed on the Royal Yacht Britannia.

An exhibition in the museum at Sandringham House includes watercolours usually hung in the Royal Family's private apartments of the racing yacht at sea and under full sail, along with photographs and a model made of solid silver from the Royal Collection.

'This racing yacht is the last word in elegance,' said Helen Walch, Sandringham's public access manager, as she put the finishing touches to the display. 'You can see she was built for speed - I'd love to have seen her go.' Britannia was 121ft long and her mast was 142ft high, carrying more than 10,000 square feet of sail. The interior included bedrooms, a bathroom, a saloon, galley and pantry, and she needed a crew of around 30 to race her.

Commissioning the Royal Yacht Britannia had been under discussion since the late 1930s as a replacement for the aging royal yacht Victoria and Albert, built for Queen Victoria and launched in 1899.

Plans were shelved as international relations deteriorated and Europe plunged towards war.

The new yacht was formally ordered just a day before King George VI's death, in February 1952.

Designed to be capable of long ocean voyages, and of being converted to a hospital ship in time of war, Britannia was formally launched and named by the Queen in April 1953, began sea trials that November, and made her first Royal voyage in April-May of 1954.

From then on, she covered an average of almost 25,000 miles a year for more than 40 years, criss-crossing the globe from America to Russia, from the Arctic to the Antarctic.

In December 1997, 14 members of the Royal Family arrived in Portsmouth to say goodbye in person to Britannia and her crew as she was decommissioned, before being towed to Leith, near Edinburgh, where she is now owned by the Royal Yacht Britannia Trust and open to the public as a visitor attraction.

Paintings, photographs and a large scale model chart her distinguished career on the seas.

The exhibition is in the museum at Sandringham House, which is open to the public from 11am - 4.30pm. Also on show this summer are a unique collection of images of the Queen from Long to Reign Over Us - a tribute published by the EDP last year when Elizabeth II became our longest-reigning monarch.