The No8, out since November with a knee injury, had virtually written off his chances of playing in the tournament but, after playing 72 minutes for Saracens against Newcastle on Sunday, he is back in the running.
Vunipola’s return will be a shot in the arm for England as they seek to equal New Zealand’s record of 18 consecutive Test wins and Nathan Hughes, who has started the last four matches, is in the firing line.
The 24-year-old, whose comeback was three weeks ahead of schedule, was man of the match in three Six Nations games last year and England have missed his massive ball carries as they have stuttered to three wins.
And the England hierarchy saw enough at the weekend to throw him straight back into international cauldron against the buoyant Scots.
Scrum coach Neal Hatley said: “He has done enough to prove he should be involved in the squad. It’s great to have the competition between him and Nathan Hughes but it’s fantastic to have Billy back.
“He brings a good boost to the boys, he’s a likeable character so he brings a good energy to the squad. It’s a confidence boost for us.
“He carried well against Newcastle and it was a good performance for a bloke who has been out for as long as he has.
“He brings really good control at the base and is one of the top carriers around. He has real power. Defensively he hits hard because of his size and he’s good over the ball. He looks in very good nick.”
England’s run of wins started in October 2015 when they beat Uruguay 60-3 in Manchester in a dead World Cup match after they had been dumped out of their own competition.
Prop Dan Cole is the only player to have started all 17 of the victories, Dylan Hartley has started all 16 under Eddie Jones and the Leicester man puts his durability down to a new recovery programme installed by the RFU’s head of sports science, Dean Benton.
Benton has worked with the Wallabies and the Brumbies plus with Jones and Japan ahead of the last World Cup and the RFU recruited him last year to beef up England’s conditioning.
And Benton’s input could explain why England have finished their last three matches strongly coming from behind to beat France, Wales and Italy.
Cole said: “Eddie has put a big emphasis on a lot of recovery work after every training and that has definitely helped myself and a lot of other boys. That off-field focus of preparing your body right has been a massive part. As a front rower your spine and hips take a big pounding so we do a lot of work with Dean Benton and it is helping us all out.
“He has brought a renewed importance of what we do. There has always been ice baths and that kind of stuff. Because we train very hard, you have to be able to recover to train the next day.
“It’s the importance of the relationship between training and recovery. That has been emphasised. You’re knackered when you get off the training field, but if you recover well you’re ready to go the next day. The boys don’t need coaches to tell them to go in the ice bath. They do it because they know it’s good for you.
“Everything we do is aligned to the performance on the field and that’s where the turn has come. You see the benefits on the field.”
