Dan Lawrence, Cameron Steel and Will Jacks were Surrey’s only spin options in the Blast last year, but the addition of Santner brings them a frontline option with more than 200 appearances in the format. Surrey have been losing semi-finalists two years in a row, and have not won the trophy since its inaugural season back in 2003.

Santner, who recently became New Zealand’s white-ball captain, will arrive in London after the IPL, where he is due to play for Mumbai Indians. He will miss the end of the group stages on international duty but should be available for the knockouts in September. He is also likely to feature in the Hundred again this year, having spent last season with Northern Superchargers.

“I’m really looking forward to connecting with the players and coaching staff at Surrey,” Santner said. “I’ve heard quality things about the environment and have thoroughly enjoyed playing at the Kia Oval previously. I’ve been fortunate to play against many of the squad so it will be great to share the same changing room and play some entertaining cricket.”

Alec Stewart, who remains involved with Surrey’s recruitment in his new role as a ‘high performance cricket advisor’, said: “Mitch will bring quality and experience to the Surrey side. He’s a proven international cricketer who plays T20 cricket all over the world and has built an excellent skillset.”