England captain Dylan Hartley delighted at Billy Vunipola return

Dylan Hartley insists England will profit from the return of "world class" Billy Vunipola for the final two matches of their Six Nations Grand Slam defence.

Vunipola has been named on the bench for Saturday's Calcutta Cup showdown with Scotland at Twickenham, after making a successful comeback from a three-month lay-off due to knee surgery.

Nathan Hughes continues at No 8 but Vunipola, England's most destructive ball carrier, is expected to come on as a second-half replacement.

"Billy's not just great to have on the training field or in a game, he's also great to have around," said England skipper Hartley.

"He's a big personality, a big, happy guy. His standards and his training habits are brilliant.

"For me, as a leader in the team, he's someone I can talk to, I can use to help me. The way he plays is world class.

"He's one of our best players and we're lucky to have someone like him to come off the bench when needed because Nathan is doing a fantastic job for us.

"It's great to see that we've got that sort of depth, that sort of competition in the team."

Hartley's front-row colleague Joe Marler will win his 50th cap in the Triple Crown decider, less than a year after he pulled out of England's summer tour to Australia after a succession of disciplinary issues had taken a mental toll.

"Physically Joe is big and strong and the way he bangs people in games... Courtney Lawes, James Haskell and Joe Marler are in the same sort of category in defence," Hartley added.

For me, as a leader in the team, he's someone I can talk to, I can use to help me. The way he plays is world class.

"He has grown in maturity and with his leadership. He's another influential person in the squad.

"He's a character, but you know when it's training or in games he'll be there, he turns up and he's driving the right standards. He performs, and you can't ask more from the guy.

"For someone that's had a few ups and downs along the way, it's testament to his character that he's knocking on 50 caps this week, so a big pat on the back for him."