Hiker Jacky Leung spotted two camera operators before realising they were filming the future queen

The Princess of Wales paused to speak with Ted Haslam, an 11-year-old boy from Sutton Coldfield who had been pushed and carried to the summit of Britain's highest mountain in a wheelchair by his father Paul and 14 other friends and relatives, during her ascent of Ben Nevis over the weekend.

Ted was left paralysed at the age of three after being diagnosed with an aggressive spinal tumour that had been doubling in size every 24 hours.

Catherine remarked on the poor weather conditions before asking the youngster: "How are you doing, Ted? You're not too cold?"

She enquired about a mascot he was holding, which belonged to Molly Ollys, a Warwick-based charity that had provided play equipment during Ted's hospital treatment.

"I'm so impressed, really, you've made it to the second peak. Super, well done you," the princess told him.

Ted's team finished their challenge in 30 hours whilst fundraising for the children's charity.

Hiker Jacky Leung also crossed paths with the princess near the summit of Britain's highest mountain, initially spotting two camera operators before realising they were filming the future queen.

Mr Leung described himself as "speechless" upon recognising Catherine, saying he felt "so confused and so psyched at that split-second" and was unable to address her properly.

The princess initiated their exchange by asking if he was alright, before enquiring whether he had reached the top.

"Yeah, we were lucky to get it to the top," Mr Leung replied, to which Catherine responded: "Well done!"

He told her: "You're so inspiring!" and she thanked him before continuing her ascent with what he described as "very strong spirit".

Mr Leung noted that few other hikers recognised the princess as she made her way upward, adding that his companions had not noticed her at all.

The Princess of Wales completed the National Three Peaks Challenge within 24 hours, having begun on Saturday evening and climbed Ben Nevis, Scafell Pike and Snowdon in succession.

Kensington Palace stated that Catherine undertook the expedition for "personal" reasons and to raise funds for The Royal Marsden cancer charity, following her own well-documented cancer diagnosis and treatment.

"I have taken on the National Three Peaks Challenge, not simply as a physical endeavour but as a chance to explore life beyond diagnosis and to give something back," the princess explained.

She added that The Royal Marsden "is a place that holds great meaning for me and whose care and expertise are life changing for so many people."

Kensington Palace believes Catherine is the first member of the Royal Family to complete the challenge.

Catherine spoke of her personal motivation for taking on the gruelling challenge, stating: "I'm so grateful to be here, to be strong enough to walk these hills. But, more importantly, it's to give something back and acknowledge, really, all the incredible work going on up and down this country."

The princess said she had encountered "incredible people" living with and beyond cancer during her trek, adding: "I know personally how difficult that journey is."

Dame Cally Palmer, chief executive of The Royal Marsden NHS Foundation Trust, expressed gratitude for the princess's support, saying it "will make a difference to the lives of so many cancer patients and their families."

Upon completing her challenge, Catherine was greeted by Prince William, their children, Prince George, Princess Charlotte, and Prince Louis, along with her parents, Carole and Michael Middleton, and her brother, James.