Boris Johnson’s favourite teacher gave him extra reading, either because he saw potential in his pupil or he was “behind” in his studies, the prime minister has revealed.

Mr Johnson spoke fondly of a teacher he named as Mr Fox, during an international chat with primary school pupils in the UK and Nairobi, joined by president Uhuru Kenyatta.

Over a live-link between the year six classroom at Cleves Cross Primary in Ferryhill, County Durham, Mr Johnson said: “I was at primary school in London, Primrose Hill in Camden.

“It was lovely, it was the same school as Ed Miliband and David Miliband.”

His favourite teacher was called Mr Fox, he said. “He decided I needed extra reading, whether he thought I had potential, whether he thought I was behind, I’m not sure.

“He took me in the library and gave me loads of books.

“I would say that’s my favourite – Mr Fox – he would be at his desk reading the Daily Telegraph.”

Mr Johnson went on to say his favourite subject later in his schooling was Latin and ancient Greek.

Laughing, he said: “They are crucial to our understanding of the modern world.”

Via the live-link, Mr Kenyatta said: “Not as important as Swahili.”

The two leaders spoke warmly to each other, often using their first names, and the Kenyan president, 59, fondly remembered a maths teacher from his youth.

“She was better looking than you, Boris,” he said.

Former Australian prime minister Julia Gillard joined Mr Johnson in Ferryhill for the link-up with Kenya. She leads the Partnership for Global Education’s project to boost girls’ learning around the world.

Speaking about the live video-link, Mr Johnson said: “It is quite a remarkable event. It would not have been possible when I was at school.

“It’s just a wonderful thing.”

Mr Kenyatta replied: “It is an incredible opportunity (when I was at school) all we had was a slide rule.”

Mr Johnson joked: “Did you get hit with the slide rule?”

Mr Kenyatta replied: “Let’s not talk about that – I was a very disciplined young man.”

Mr Johnson said he looked forward to seeing the president in London in July, when there will be a summit and fundraiser for the international girls’ education initiative.