Speaking on BBC One's Breakfast With Frost programme, she said one of the worst moments had been when the balloon lost contact with the Geneva control centre over the Pacific.

The balloon made a safe landing in Egypt

"Not to have human contact by voice or even by data link when you are in the middle of a big wide ocean can be a bit distressing. It was unfortunate for them and for us."

Her husband and the support team, she said, had been "quietly confident" of succeeding.

"We all were in our own way but you don't like to express it, it is very much one day at a time."

The 45-year-old has worked in the control room since the balloon launched from Switzerland three weeks ago.

She told David Frost she had not yet been able to speak to her husband on Sunday morning and that it would take some hours to reach the men after their successful landing because they were quite a distance from a tarmac road.

"It is a great celebration and a great joy and we are all so proud of them. It is a fantastic feat."

'In awe of the achievement'

She added of her husband: "I don't know what you do to top this. He is not an adventurer, I don't think he will go looking for it although this may have given him the taste for it.

"But I would assume for a couple of weeks we will take a holiday and catch our breath and see what happens next."