Former British & Irish Lions skipper Martin Johnson believes Scotland have once again discovered a winning formula under Vern Cotter and are back as a genuine force in world rugby after a sparkling Six Nations to date.

Scotland claimed their first win over Wales in ten years last time out; Cotter's side coming from 13-6 down to beat the Welsh 29-13 in their encounter at Murrayfield.

That memorable victory over Rob Howley’s Wales has seen them rise to their highest-ever position of fifth in the World Rugby rankings, with the likes of South Africa, the Welsh and now France below them in the listings.

It is the first time since 2006 that Scotland has won two of their first three Championship matches and Cotter’s men are now targeting a first win at Twickenham since 1983 on Saturday.

Scotland must still improve however if they want to end a 34-year losing run at Twickenham and win a first Six Nations Triple Crown since 1990 – but Johnson is convinced Cotter’s side are doing things the right way.

“They have found a way to win games suddenly,” said World Cup winner Johnson. “That was a game Wales would have been thinking they should have won but Scotland won it and they have got over that hurdle again.

“They have beaten Ireland, beaten Wales and now one game away from winning a Triple Crown.

“I thought Wales were on top early on but Scotland kept on going and were tenacious and had more of a cutting edge.

“Their backline is opening teams up, not just Hogg, they are opening teams up and creating opportunities to score tries.

“Ultimately you can win games without scoring two tries, or even any but you are not going to win many, so you have got to get over the line a couple of times, three times ideally. 

“It was a game they could have lost, they could have gone to pieces but they kept on going, they are dealing with injuries as well.

“They have depth in the back row, the Gray brothers need to keep on doing what they do, the scrummage is not great but they know that.

“I think when you know you can deal with it mentally, if you go out and think you can scrummage when you can’t, it can play on your mind.

“The guys on the front row give it everything around the park and they play well at times, they do what Scotland do and make it hard to play but they have a little bit more cutting edge.

“They have skills and pace as well as being tenacious and tough and great under the high ball. It is not always going to be ball in hand, you must do your entire job as a winger, chasing it and putting people under pressure and they made people miss tackles.”

A host of Scottish backs caught the eye against Wales – try-scorers Tim Visser and Tommy Seymour, as well as full-back Stuart Hogg was outstanding in Edinburgh.

But it was the performance of fly-half Finn Russell, who was deadly with the boot throughout, that made the difference against Wales according to Johnson.   

“As a ten you touch the ball more than anyone else and you can direct the game so you are more influential than any other player,” added Johnson. “He was outstanding against Wales.

“I think Finn Russell is playing well, you can see a little bit of confidence growing in him. I think he’s a guy that doesn’t get a lot of headlines but has got to do his job and he does it well.

“I thought the whole back three were generally good as well. I think for me the heart and soul of the Scotland team is that back five of the scrum, with the nine being tenacious, getting stuck in a making things difficult and awkward, plus Russell pulling the strings – it’s exciting.”

Martin Johnson is an Ambassador for British & Irish Lions Principal Partner Standard Life Investments.