Prince Edward was seen driving to the Royal family's annual pre-Christmas lunch in a Range Rover adorned with Prince Philip's OXR1 plates.
This registration had been used by the late Duke for many years, starting with a custom 1954 Lagonda 3-litre drophead coupe which he kept until 1961.
Later on, the Lagonda was replaced by an Alvis TD21, which was eventually restored and exhibited at the Sandringham museum still bearing the same number plate.
Prince Philip also drove a Land Rover Discovery with the registration plate OXR 2.
Accompanying his wife, the Duchess of Edinburgh, and daughter Lady Louise to the family gathering at Windsor Castle, the youngest son of the late Duke drove the car.
The King hosted the private event for the second year in a row at Windsor Castle, breaking tradition by choosing this location over Buckingham Palace.
The holiday meal featured a feast of turkey and all the traditional side dishes, marking the largest family reunion since the Coronation in May.
Notable guests included the Prince and Princess of Wales, the Princess Royal with her husband Vice Admiral Sir Tim Lawrence, the Duke of York, Princess Eugenie with her husband Jack Brooksbank, Zara and Mike Tindall, and Prince and Princess Michael of Kent.
Also present were Lord Frederick Windsor with wife Sophie and children, Peter Phillips with his two daughters, and close friend of the late Duke of Edinburgh, Penny Romsey, the Countess Mountbatten of Burma.
Over 50 extended family members gathered at the festive lunch, enjoying Sandringham-bred turkey followed by Christmas pudding, along with champagne and wine.
The celebration included crackers, jokes, and party hats, while the younger royal children typically had a separate dining arrangement with their nannies.
Traditionally held at Buckingham Palace, the decision to host it at Windsor Castle this year was a personal choice made by the King.
While the late Queen used to travel to Sandringham by train the next day and stay until the anniversary of her accession on February 6, the King will also head to Sandringham but will have a shorter stay before returning to work.