A new triple-portrait of the Prince of Wales and his sons is featured in a set of Royal Mail stamps marking Charles’ 70th birthday.

Charles, the Duke of Cambridge and the Duke of Sussex were photographed during the July celebrations at Buckingham Palace that marked the RAF’s 100th anniversary.

William served for a number of years as an RAF Search and Rescue pilot, Harry is Honorary Air Commandant of RAF Honington while their father is Marshal of the Royal Air Force.

The image is one of six that show the heir to the throne at work and play in celebration of his birthday on November 14.

Polo princes is the theme of another stamp, with William and Harry sharing a joke with their father during an event at Cirencester Park Polo Club in 2004, when they took part in the Gurkha Welfare Challenge Trophy.

Charles, Harry and William during a day playing polo at Cirencester Park Polo Club. Barry Batchelor/PA Archive

Charles’ Scottish retreat, the Castle of Mey, is the backdrop for a portrait of the prince on another stamp.

While a scene showing the heir to the throne greeting schoolchildren during a visit to a Tudor manor house, Llancaiach Fawr Manor near Cardiff, has also been chosen for the collection.

The final two stamps feature an image of Charles hugging wife Camilla – which was used for the couple’s 2015 Christmas card – and a photograph of the prince by himself.

Three of the stamps are first class with the remaining trio priced £1.55, and all are contained within a special miniature sheet.

They are available to pre-order from the Royal Mail website and go on general sale from Thursday.