The Queen: Heroic Portsmouth sailor Sir Robin Knox-Johnston recalls Elizabeth II's 'radiant smile' from multiple encounters with the late monarch

Portsmouth's Sir Robin Knox-Johnston was the first person to sail solo non-stop around the world, a route now followed by the Clipper World Race.

Along his journey he battled 80ft waves, shark attacks and even appendicitis - not learning about the latter until a year later, when doctors revealed his appendix had burst and re-healed itself.

After his return to UK shores 53 years ago, he was invited by Her Majesty the Queen to Buckingham Palace for lunch.

He said: 'There was a large number of guests there so her time was being shared between everyone, but she was very natural in how she carried herself.

'I was acutely aware of how she put people at ease - before long she and I were chatting like we had known each other for years.'

When Sir Robin was 13 years old, he saw Elizabeth II's coronation take place right before his eyes, standing just 10ft away from the monarch as she passed through Hyde Park.

He now lives in Old Portsmouth, and is the mastermind behind the Clipper Boat Race - an annual race around the world in 11 identical yachts with professional skippers, but amateur crews.

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His final encounter with Queen Elizabeth II came in 2016, when the pair met at his old school.

He said: 'She was visiting my old school and came along for the day - I was fortunate enough to sit next to her at lunch.

'Her Majesty was utterly fabulous, I think she genuinely spoke to everyone during that lunch break and you could see on her face just how much pleasure it gave her to chat with people.

'She took a genuine interest in everyone, which will have made such precious memories for so many young people.

'There was so much adoration and respect for her, no matter where she went.'

Sir Robin added that he will always remember the Queen's 'radiant smile' and how she commanded huge respect right across the world.

'She gave this country stability - everyone knew she was there and that she could be relied upon,' he said.