In a performance full of bravery and composure, Duhan van der Merwe scored the crucial try to help the Scots to their first triumph at English rugby’s HQ since 1983.
The visitors were worthy winners, taking the game to the highly fancied hosts from the first minute.
England were priced at 1-6 to win with most bookmakers but Scotland made a mockery of the odds. Captain Stuart Hogg and his team will now go down in history as the side who were able to slay England in their own den, emulating Jim Aitken’s heroes of ’83.
Finn Russell and Owen Farrell kicked two penalties apiece but it was the Scotland stand-off who ruled the roost - despite a ten-minute sin-binning for an attempted trip on England scrum-half Ben Youngs.
His flair and vision were key to the win but there was also superlative performances from debutant Cam Redpath, Hogg, Matt Fagerson and hooker George Turner, the latter making his first appearance in the Six Nations.
The importance of the first 20 minutes had been repeated like a mantra inside the Scotland camp in the build-up and the message clearly penetrated. The visitors were composed and disciplined, in sharp contrast to the way they played in the early stages during their previous two visits to Twickenham.
Turner looked assured, picking out his men at the lineouts, while Redpath was seeing plenty of the ball and also looked the part as the Scots probed for opening.
The only fly in the ointment seemed to be Maro Itoje whose rushing of Ali Price was causing a couple of problems. The Scotland scrum-half saw his kicks charged down not once but twice by the formidable England lock.
Scotland had started brightly and when Jonny Gray won good lineout ball the platform was set. Turner went on the charge as the Scots tried to force their way over and they were eventually awarded a penalty when Itoje was judged to have gone over the top.
Russell collected the three points from in front of the posts.
England were leaking penalties as Scotland played with pace and variety. Russell was starting to find his range and when he threaded through a grubber to Sean Maitland the winger did well to gather and keep the ball in play. Unfortunately, his pass inside just eluded Russell.
Nevertheless, the first 20 minutes were up and Scotland looked the dominant side, a scenario that must have pleased Townsend greatly.
Farrell was warned by referee Andrew Brace that England needed to cut down the penalties but they failed to heed the warning and a minute later Billy Vunipola was shown the yellow card for tackling Russell around the neck.
The question now was could Scotland turn their superiority and numerical advantage into points?
The answer came fairly quickly. Matt Fagerson firstly tried to force his way over and when he was repelled, Price fed to Hamish Watson whose surge for the line fell just short thanks to heroic defending from Ellis Genge and Tom Curry.
But Scotland kept up the pressure and after a succession of collapsed scrums they eventually managed to get the ball out. Redpath slipped the ball to Russell who delivered a delightful right-footed dink to the corner but the bounce just eluded the outstretched arms of 6ft 4in winger Duhan van der Merwe who signalled that he was just inches away from gathering.
But the big Edinburgh man delivered a minute later. Russell’s cross-field kick triggered the score which involved a bustling run from Matt Fagerson and a fine pass from Redpath to Turner. The hooker played in van der Merwe but the winger still had plenty to do and took a few white shirts with him, eventually outmuscling Mark Wilson to force himself over for the try.
Russell’s conversion attempt went narrowly wide but Scotland were 8-0 up with ten minutes of the half remaining.
And then England woke up. When Rory Sutherland conceded Scotland’s first penalty of the match from open play it gave Farrell the chance to put points on the board for England with a long-range penalty, which he duly did.
Redpath was then a little too quick off his marks and ruled offside, giving Farrell the chance to reduce the lead further. But before he could take the penalty there was a dramatic intervention from Irish TMO Joy Neville. She had spotted Russell trying to halt Youngs with his outstretched right leg and the Scotland stand-off was punished with ten minutes in the sin-bin.
Farrell finally kicked the penalty, making it 8-6 at half-time to Scotland, a scoreline that barely reflected the dominance of the visitors
The Scots managed well in the opening moments of the second period without their playmaker and when Genge was punished for a no-hands tackle on Turner, it coincided with Russell’s return and he despatched the penalty to increase Scotland’s lead to five points.
But Russell was guilty of bad miss with his next attempt at goal, his penalty attempt drifting wide.
Scotland continued to press and on their sixth incursion into the opposing 22 England secured a crucial turnover
With 17 minutes remaining, Townsend opted to freshen up his pack, bringing on props Oli Kebble and WP Nel and back-rower Gary Graham.
Reserve hooker Dave Cherry soon joined them, winning his first cap for Scotland, as did sub scrum-half Scott Steele, winning his second.
Scotland continued to battle hard and Redapth won an important turnover. The visitors were awarded a penalty and captain Hogg had a mighty boot at it from halfway but his attempt went wide as the minutes ticked away.
England: E Daly (Saracens); A Watson (Bath), H Slade (Exeter), O Lawrence (Worcester), J May (Gloucester); O Farrell (Saracens, capt), B Youngs (Leicester); E Genge (Leicester), J George (Saracens), W Stuart (Bath), M Itoje (Saracens), J Hill (Exeter), M Wilson (Newcastle), T Curry (Sale Sharks), B Vunipola (Saracens).
Replacements: L Cowan-Dickie (Exeter), B Obano (Bath), H Williams (Exeter), C Lawes (Northampton), B Earl (Bristol), D Robson (Wasps), G Ford (Leicester), M Malins (Bristol).
Scotland: S Hogg (Exeter, capt); S Maitland (Saracens), C Harris (Gloucester), C Redpath (Bath), D van der Merwe (Edinburgh); F Russell (Racing 92), A Price (Glasgow); R Sutherland (Edinburgh), G Turner (Glasgow), Z Fagerson (Glasgow), S Cummings (Glasgow), J Gray (Exeter), J Ritchie (Edinburgh), H Watson (Edinburgh), M Fagerson (Glasgow).
Replacements: D Cherry (Edinburgh), O Kebble (Glasgow), WP Nel (Edinburgh), R Gray (Glasgow), G Graham (Newcastle), S Steele (Harlequins), J van der Walt (Edinburgh), H Jones (Glasgow).
Referee: Andrew Brace (Ireland).