King Charles and Queen Camilla toured the Royal Infirmary of Edinburgh, meeting dozens of medical staff, patients and the public to mark the anniversary.

The National Health Service - the world's best-known health system - came into being on 5 July 1948.

It was launched by then health secretary Aneurin Bevan at Park Hospital in Manchester - today known as Trafford General Hospital.

When Queen Camilla spoke to a group of elderly patients, she commented about the anniversary: "I'm 75, I'm the same age as the NHS - we share a birthday."

Nearby the King also spoke to some of the Infirmary's oldest patients and quipped about his age - 74.

He said: "You get to the age I am, things don't work as well as they used to," before joining his wife to cut an NHS birthday cake.

The royal couple were given a tour of the hospital, meeting maternity staff from midwives to obstetricians, before they talked to those caring for patients coming towards the end of their lives.

In the hospital's reception, a huge crowd was waiting to see the King and Queen after word got around they were visiting.

Queen Camilla stopped to talk to doctors Zack Hassan, 28, and Robert Cronshaw, 29.

Dr Hassan, who when not working on the wards hosts the Healthy Discussions podcast, said: "She said to us, 'doctors are looking younger every year' and that's something I hear from my patients."

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Earlier on Tuesday, the couple unveiled a plaque at Holyrood Palace, marking the Jubilee Gates which were installed last year as a gift to the late Queen Elizabeth II.

A garden party will be held later in the day, a traditional part of Holyrood Week.

On Wednesday, the King will be presented with the Honours of Scotland - the nation's crown jewels - at a special ceremony of thanksgiving at St Giles' Cathedral in the capital.

The festivities will also include a People's Procession, a Royal Procession, a 21-gun salute, and a flypast by the Red Arrows.

Public viewing areas will be available along the Royal Mile. All those wishing to attend are being urged to arrive early and prepare for changeable weather conditions.