Publishedduration15 minutes agoimage copyrightChris Jackson/Getty Images

The Queen and Duke of Edinburgh have marked their 73rd wedding anniversary by releasing a photograph showing them opening a card from the Duke and Duchess of Cambridge's children.

The homemade gift was created by Prince George, Princess Charlotte and Prince Louis and is emblazoned with 73.

The photograph was taken earlier this week in the Oak Room at Windsor Castle.

The Queen, 94, was a 21-year-old princess when she married Lieutenant Philip Mountbatten on 20 November 1947.

Their enduring relationship has lasted the longest of any British sovereign.