Joe Marler is the frontrunner to be England’s starting loosehead at the World Cup later this year, and fellow Red Rose prop Dan Cole insists the Harlequins skipper has truly come of age.

If his form holds and injuries stay away, Marler is set to beat British & Irish Lions Alex Corbisiero and Mako Vunipola to the number one jersey ahead of England’s World Cup curtain-raiser against Fiji on September 18.

It is all down to a remarkable two-year stint for Marler, having capitalised on injuries to assert himself in the England pack before ascending to the Harlequins captaincy last season in place of Chris Robshaw.

Key to that has been a coming of age, ditching the ill-discipline that saw him a pick up a rash of sin-bins earlier in his career.

And tighthead Cole – who is also likely to be first-choice tighthead – has seen the 25-year-old grow up before his very eyes.

“First time he came on the scene he obviously had talent, and his maturity and understanding of the game – in terms of where he needs to be, his head needs to be – he’s evolved in,” said Cole.

“Especially as captain of Harlequins, it’s a big responsibility and he’s done it incredibly well.

“He’s taken that on into his international career and now he’s one of the best looseheads around.

“He played exceptionally well at the Six Nations and he’s really motored on over the last year.

“There is some great competition at loosehead, you’ve also got two British & Irish Lions in there in Mako [Vunipola] and Alex Corbisiero, and Matt Mullan who’s been very good for Wasps this year.

“There’s that depth there and it’ll be really up to these next eight weeks for people to really put their hand up and take that spot. They’re all good guys, they’re all fighting each other, and England will all be stronger for it.”

The current 45-man squad are undergoing gruelling high-altitude training in Denver in preparation for their first warm-up Test against France on August 15.

And according to Cole, England won’t just be relying on either himself or Marler to prop up the front-row.

“You look at [reigning champions] New Zealand in 2011 and they were down to their fourth or fifth fly-half by the World Cup final, so you need a good squad depth,” he added.

“Injuries do happen, it’s not going to be 15 blokes to win you the World Cup, you need the 31-man squad and also even players outside that.

“I can remember my first game, the first game of the Six Nations in 2010, and as time goes on you probably become more confident in your abilities.

“But you never lose the nerves or excitement for international rugby, every game is unique and you remember each one.”

Dan Cole was appearing alongside his England team mates at the launch of the innovative England Rugby World Cup shirt #CommittedtoEngland. Visit Canterbury.com