The secret behind the perfect Royal photograph

A picture of the Queen, the Prince of Wales, Prince William and Prince George, for stamps to mark the monarch's 90th birthday, has been released.

Ranald Mackechnie was the photographer of the official portrait at Buckingham Palace. He told Radio 5 live Daily's Peter Allen that he only had a 45-minute window to take the perfect picture.

"We were given up to about 45 minutes and we got it in nearly 25. Once we knew we had it, we said thank you very much and let them get on with their business."