Chandler Cunningham-South’s rapid rise to international rugby has caught even the 20-year-old by surprise but, for all the high-profile coaches he has crossed paths with in a short space of time, the England flanker’s toughest critic is on the other side of the world in New Zealand: his father.

Cunningham-South earned rave reviews after his England debut against Italy, with Sam Warburton saying the Harlequins blindside is “the real deal”. He looks destined for a lengthy career at the top but he remains grounded, thanks in no small part to regular progress reports from back home telling him exactly where he needs to improve. “That’s still the case,” he says with a smile when asked if his father continues to critique him.

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“Pre- and post-game, I get my reports from him so he tells me what I should be doing. It’s in a WhatsApp and it’s like a script – you have to click to read more and see it all. It’s all good, it’s all motivation and it’s really helpful.

“He’s got a pretty decent rugby head. He used to coach me when I was young, for my last year before I went to high school so he has got a little bit.”

Who is the harsher critic: the England coaches or his father? “Probably my dad,” he says. “He played a little bit but nothing crazy. I didn’t get one [a report] from the last game so I don’t know if that is a good thing or not. The games before it was: ‘Keep trying to make an impact, keep working hard.’”

Cunningham-South has certainly delivered on that advice. His three appearances from the bench have caught the eye in one of the biggest tournaments there is: a far cry from where he found himself two years ago.

Rejected by the Christchurch-based Crusaders in New Zealand – where he grew up after moving there from Sidcup at the age of four – Cunningham-South decided to chance his arm and try to build a career in English rugby. “I was 18, playing at Lincoln University [near Christchurch]. I wanted to be in an academy setup but nothing came to fruition,” he says.

“The Crusaders academy didn’t have a place for me, so I got in touch with an agent and he got a highlights reel together and started to look elsewhere. Then I got the opportunity over in England [with the London Irish academy] and it has all happened pretty quickly since I got over here.”

Cunningham-South has certainly crammed plenty into his short career. He was given a chance by Irish in 2022 but just as he was beginning to find his feet their well-documented financial crisis struck. That left him without a club once again until Harlequins came in for him last summer. Still, he describes that one year with Irish as some of his most formative experiences in his playing career and his life.

“All the coaching staff there were great,” he says. “John Fisher was very helpful, Les Kiss, Declan Kidney … all of them were very good men and helped me a lot.

“They developed me a lot, especially the professional side of it, and even as a person. I was only 18 so it wasn’t just coaching they were having to do, they almost had to be helping me out on a personal level as well, making sure I was OK.”

Having come such a long way so quickly, surely he finds the noise and euphoria that accompanies games such as last Saturday’s Calcutta Cup difficult? “It’s nice, I like it,” he says with a smile. “Especially when we were up in Edinburgh getting off the bus. All the heckling and yelling – that sort of stuff motivates me and gives me an extra bit of energy.

“Twickenham is awesome to play at. So loud, so passionate … it’s a real cool place to play.”

Having not been in a full-time environment until the age of 18, Cunningham-South admits he still has plenty of learning to do, which is a terrifying thought given how he has acquitted himself so far in an England shirt.

“I haven’t had a chance to stop and reflect and have to keep looking forward to what’s next,” he says. “I didn’t realise how much detail went into the professional game and we didn’t really do analysis at university. Sitting in the meetings going over that stuff was a bit of a shock.”

It is a long way from the days of being rejected by academies in New Zealand and you suspect his story still has a lot of trajectory left in it. His parents will fly in for next Saturday’s game with Ireland from their farm in Wellsford, north of Auckland, meaning this time the post-game review with Dad will be conducted in person. You suspect, given how Cunningham-South has played thus far, it will not be too scathing.