England head coach Eddie Jones has explained why he picked Willi Heinz as one of just two scrum-halves in his 31-man World Cup squad.

The Gloucester captain only won his first cap in Sunday’s warm-up win over Wales at Twickenham but has impressed since being involved in training camps throughout the summer.

His emergence as a contender to go to Japan came as a surprise as his only previous involvement was during a training camp in Brighton two years ago.

With the experienced Danny Care being overlooked since last year’s autumn internationals, Heinz has jumped the queue ahead of Ben Spencer and Dan Robson, who both played during the Six Nations, to provide back-up to the established Ben Youngs at nine.

Heinz captained Gloucester as they finished in the Premiership play-offs last season, scoring four tries in 17 appearances as he caught Jones’ eye.

“We’ve struggled to find the right combination there,” said Jones.

“We got Willi in before the Argentina tour in 2017 and he was okay but we didn’t invite him back for a while.

Willi Heinz of England is tackled

“He knew what he had to work on, went back to his club and I thought he was outstanding for Gloucester last season. Therefore we got him into camp again.

“He’s improved his game, he’s a great communicator which we’re not overly endowed with and that was one of the significant reasons why he has earned his selection.”

Jones accepts he has taken a gamble by taking just two specialist scrum-halves and said George Ford could play there in an emergency.

“He's been doing some training there and he'll continue to do that,” said Jones.

"If we need a third half-back then we feel he can fill the role for a period of time.

“It is one of those balance of the squad things. I think the most injury-prone areas at the moment are outside backs because of the amount of high-speed running they have to do now.

George Ford of England

“If you look at the Test yesterday (against Wales) compared to the Six Nations Test there was 30 per cent more high-speed running.

“The physical demands of the game for the outside backs now are enormous because of the kick-chase and the kick-sprint.

“We didn’t feel we could go one short in that area and we have taken a gamble.”

Former Gloucester academy player Sam Underhill was named in the squad and could return to face Ireland later this month having been ruled out of the reverse match against Wales at the Principality Stadium on Saturday with the toe injury that forced him to withdraw last weekend.

With Tom Curry also going off injured in that game, former Gloucester flanker Matt Kvesic has been called up to train with the squad this week along with Bath lock Charlie Ewels and Harlequins centre Joe Marchant.

Exeter centre Henry Slade has been sidelined for three weeks with a knee problem and his Exeter team-mate Jack Nowell is “on track” for the World Cup despite a setback on his ankle injury.