Joe Marler is poised to complete a remarkable comeback from his fractured leg when England launch their Grand Slam defence against France on Saturday.

Marler was told he would be sidelined for five weeks after withdrawing from the warm-up of Harlequins' victory over Sale on January 7, effectively ruling him out of the opening two rounds of the Championship.

But having resumed full training in last week's Portugal training camp, the loosehead prop is set to start the showdown with France at Twickenham.

"Joe is looking good and has been taking a full part in training," forwards coach Steve Borthwick said.

"He's a fast healer! He's done really well, he has been incredibly diligent in terms of doing everything he can to get fit. That's great credit to him."

The news is an enormous boost for England, who are likely to be without first-choice loosehead Mako Vunipola for the entire RBS 6 Nations campaign because of a knee problem.

Vunipola and Marler have been locked in fierce competition for the position, with the former edging ahead last year with a series of world-class displays for Saracens and England.

"It's great that we have that competition for places at loosehead and we're trying to build that in every single position," Borthwick said.

"We want top international players competing hard and pushing each other. That's what Joe and Mako did last year.

"There have been a couple of knocks and bangs since, but it's great to have players of that quality."

England have received further good news on the injury front after James Haskell and Jack Clifford were cleared for their opening match of the 2017 RBS 6 Nations.

James Haskell is nearing his return from injury too (Getty)

Haskell has made two brief appearances for Wasps since returning from toe surgery earlier this month but after seeing a specialist to assess the residual soreness he felt in the foot, he has been cleared to play.

The flanker is unlikely to start, however, given his lack of match fitness with Tom Wood likely to continue at openside.