New Zealand-born Lions coach Warren Gatland – who called it “the toughest tour” – gave surprise call-ups on Wednesday to Ireland fullback Jared Payne – also born in New Zealand – England wing Jack Nowell and Wales back-rower Ross Moriarty.

Warburton stood down from the Wales captaincy this season and is currently out with a knee injury.

But he is expected to be fit before the squad departs on May 29 for a tour that will feature a three-test series against world champions New Zealand.

“I had a dinner with all the other former captains last night when it sunk in, the enormity,” said Warburton at a news conference after the squad was announced.

“I found out last Thursday when Gats called. I was in a supermarket car park and didn’t believe him at first.”

Warburton was the skipper and Gatland, again on secondment from his job as Wales boss, the coach when the Lions won 2-1 in Australia four years ago.

“Sam is a great player, an outstanding leader and a winning Lions captain,” said Gatland.

“We believe that Sam’s experience and leadership qualities make him an obvious choice as captain.”

While Hartley was left out, rival England hooker Jamie George was included, along with Ireland captain Rory Best and Wales’ Ken Owens.

Hartley was not the only notable England omission, with in-form lock Joe Launchbury also missing out.

During the Six Nations, Launchbury deputised for injured lock George Kruis, who was selected by Gatland after recently returning for Saracens.

Borthwick knows better than most how Hartley must feel at being left out of the Lions squad.

Borthwick, now an assistant to Gatland, suffered a similar fate when, as the then-England skipper, he too was omitted from the combined side’s squad for their 2009 tour of South Africa.

“I know that Dylan will be very disappointed not to be selected,” said Borthwick.

But the former lock added the experience Hartley had gained through a chequered career that has seen him sidelined for more than a year because of suspension would help him cope with this ­latest setback.

“The thing about Dylan, one thing that’s really struck me is just how resilient he is,” said Borthwick, who has got to know Hartley while working as an assistant to England coach Eddie Jones.

“He’s bounced back from a lot of things, he’s a strong character.”

Six Nations champions England have the largest national contingent, with 16 players in an unusually large 41-man squad.

Wales have 12 and Ireland 11 with Scotland’s two representatives, fullback Stuart Hogg and wing Tommy Seymour.

Gatland’s squad will be aiming to become just the second Lions party to win a test series in New Zealand, with the combined side’s lone series success against the All Blacks coming in 1971 – when tour manager John Spencer, the former England international, was in the squad.

They begin their 10-match tour against a Provincial Union side in Whangarei on June 3, with the first of three tests against the All Blacks in Auckland on June 24.