A special service for the Queen Mother was held at St Paul's Cathedral

The Queen Mother, the youngest daughter of the Earl of Strathmore, is pictured sitting behind her future mother-in-law, the formidable Queen Mary, wearing a fashionable cloche hat.

The image, taken at the time she was being wooed by the future King George VI, is one of the few formal portraits in the collection.

Others show a relaxed Queen Mother, at home on her native soil, two of which were taken during WWII.

The King and Queen toured the Clyde's shipyards as they echoed to the sounds of the war effort, and the young Queen Elizabeth was caught by press photographers laughing with women workers clad in boiler suits.

Royal walkabouts

The second picture shows the Queen Mother chatting with tea boys in an Edinburgh factory. It also captures the royal walkabouts which she invented and which made her one of the most-photographed women of the century.

But the exhibition also shows life away from the public eye at her home in Glamis Castle, where she lived for much of her childhood, and the royal retreat of Balmoral, as well as her own Castle of Mey in Sutherland, where she holidays each year.

The show is due to run until September 15.

Later this month, Edinburgh will host a tribute to the life of the Queen Mother, when the armed forces mount a musical birthday celebration.

Edinburgh Castle will echo to the sounds of the massed pipes and drums in a series of her favourite military tunes.

The celebrations come just before her 100th birthday on 4 August.