The Duchess of Cornwall has described herself and the Prince of Wales as still having “a snap in our celery” as she stressed their foreign tours were working trips and not holidays.

Camilla’s comments were made on the flight home from the Middle East where the royal couple spent four days celebrating the culture, heritage and achievements of Jordan and Egypt.

Royal tours are conducted on behalf of the Government and usually feature busy schedules, covering thousands of miles and the duchess described this week’s trip as “quite tough”.

The highlight of her time in the Middle East was the royal couple’s visit to the site near the River Jordan where John the Baptist was said to have baptised Jesus, describing it as a “spiritual” moment.

Speaking on Voyager, the ministerial jet, before it landed on Friday, the duchess said about the Middle East tour: “It was quite tough, we were driving a lot and it was pretty bumpy.”

Commenting on her previous visit to Egypt with Charles, soon after they married, she added: “But afterwards I think, OK, 16 years ago, I’m a lot older now, well into my 70s but to quote Richard Ingram, ‘we’ve still got a snap in our celery’.”

Since marrying Charles in 2005, the duchess has travelled the world visiting everywhere from Colombia and the Galapagos Islands to Jamaica, Mexico and New Zealand in support of the UK.

On Thursday, Charles and Camilla toured the pyramids at Giza, on the outskirts of Cairo, and also posed for pictures in front of the Sphinx.

The duchess added: “We are not on holiday, we might be dressed up and photographed against the pyramids like tourists but we are not on holiday. We are working for the Government and country and we are trying to make a difference.”

Camilla said their visit to the baptism site of Christ in Jordan was the highlight of the trip for her: “It was extraordinary, something you read about. To actually go down there and experience it – it was really quite spiritual.”