Luatua said: "Giving up the All Blacks jersey, especially ahead of the Lions tour, was the hardest part. I do have ambitions to play at a World Cup, maybe in 2023…"
Luatua missed the 2015 World Cup defence and played his last test in 2016. He found excellent form for the Blues in 2017 and the All Black loose forward stocks are being tested with Jerome Kaino near the end of the road and injury-hit captain Kieran Read not far behind.
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On playing for promotion-chasing Bristol, Luatua said: "When I found Bristol were in the second division, I prepared for the worst.
"I was expecting to play in front of small crowds on pitches that aren't taken care of. It has been better than I expected. Playing in some of these little towns has been humbling.
"My first away game was at Cornish Pirates. I'd gone from Eden Park to Ashton Gate to a field with no stands and an old school changing room.
"Early on, I would always see a few guys lining me up. I got smoked a couple of times but it's all legit."