John Key’s first courtesy call to press the flesh in London as New Zealand prime minister included some lighter moments.

As well as meeting the Queen, London’s eccentric mayor Boris Johnson and the All Blacks, in a touching moment Key met his half brother Martyn Key, 68, for the first time.

Martyn, his wife Carole and son Milo met the new PM in a London hotel and discussed their shared father George and other personal issues.

John Key, 20 years Martyn’s junior, said: “It was a great meeting and a fairytale story to come out of the election. The New Zealand Herald played the dating game.”

Martyn Key said: “We had a lot to catch up on”, adding that the pair talked about “personal things”.

He added: “I used to look like that (John) when I was younger.”

Martyn Key said he had been following the election all the way through.

“He’s very charismatic. This is all absolutely surreal. I’m stunned but very proud.”

John Key said Martyn looked “a bit like my Dad”.

The pair now plan to meet in New Zealand, with Martyn laughing: “I’m sure I’ll get a visa now!”

Earlier in Key’s whistle-stop 24-hour tour, he and Boris Johnson joked about Saturday’s All Blacks-England rugby clash.

Johnson said New Zealand’s “colonial masters” would win, adding he was a “great admirer” of Key’s “warrior spirit” for flying over.

After a longer than expected meeting with the Queen and Prince Philip, Key said he was not a fan of republicanism, but that there would be no return to knighthoods in New Zealand under his premiership after their removal in 2000.