'For people that probably don't know him, he's a lot like a small Michael Hooper'

Billy Vunipola says the absence of Dylan Hartley through injury will be a "massive" loss to England but has backed Saracens colleague Owen Farrell to thrive as the team's sole captain.

Farrell was promoted to co-captain alongside Hartley during the November internationals, having filled in for the Northampton Saints man on the June tour to South Africa.

It was confirmed by coach Eddie Jones on Thursday that Hartley will miss the start of the Six Nations with a knee injury, ruling him out of a Dublin showdown with defending champions Ireland, who completed the Grand Slam at Twickenham last year.

But some believe it is Farrell who will end up leading England into this year's Rugby World Cup in Japan and Vunipola says the 27-year-old has the character to fill the leadership void left by Hartley against Ireland.

"It'll be massive," Vunipola told Omnisport, speaking on behalf of Land Rover. "Dyl's been there from the start with Eddie and they run a tight ship but a fun ship.

"He's a great leader and we'll definitely miss him in and around camp. He's a great guy and a great captain as well, so we'll definitely miss him.

"But I think Faz [Farrell]... everyone knows the standards he sets and hopefully he can set them for us and lead by example."

Vunipola added that both men command the same amount of respect in the squad, commenting: "They're kind of the same body with two different heads. Everyone listens and everyone respects [what they say]."

The Saracens number eight said it was "lovely" to see his name in Jones' squad after injuries have limited his involvement in the past two championships to just two appearances in 2017.

He is joined in the squad by clubmate and fellow back-row forward Ben Earl, who - along with Ollie Thorley, Dan Robson and Jack Singleton - is one of four uncapped players to make the cut.

"For people that probably don't know Ben Earl, he's a lot like a small Michael Hooper," Vunipola explained, despite the fact that Earl is two inches and a kilo heavier than the Australian.

"He's strong, he's powerful, he's compact, but he's fast. He's good over the ball and I'm just happy to have another Saracens team-mate in the team.

"It's testament to the system we have here.

"I know he'll do well in training, but we're all pushing for the same spot, so we just have to push each other as much as possible."

Billy Vunipola is a Land Rover ambassador. Land Rover shares and understands the values of rugby. @LandRoverRugby