William welcomed his grandparents to the base of the East Anglian Air Ambulance (EAAA) at Cambridge airport where he has been working for more than year.

The Duke was on duty during the royal visit and was called out with his crew - co-pilot, doctor and critical care paramedic - to a medical incident just over 90 minutes before the royal couple arrived.

But he was back in time to greet his grandparents and landed near the new base, constructed off-site before being erected close to the landing strip last year.

The Queen and Philip arrived by helicopter around 20 minutes after their grandson and he was waiting in a room in the base to greet the pair.

He kissed his grandparents on both cheeks and the Queen said: “You are only just back,” and her grandson replied yes we just made it.

William later told Philip he had spotted their helicopter in mid-air after his crew had been called out to the incident in King’s Lynn, which is close to the Queen’s Sandringham estate.