England placed one hand on the RBS 6 Nations trophy and teed up a shot at the Grand Slam after scrapping their way to an ugly victory over Scotland.
Martin Johnson's men head to Ireland next week knowing a victory will seal the first Red Rose clean sweep since the World Cup-winning year of 2003.
England's points difference is so great, courtesy of their thumping victory over Italy, that they should be crowned champions even if they lose in Dublin.
Scotland, who have not won at Twickenham since 1983, must beat Italy next weekend to avoid the wooden spoon.
England led 12-9 courtesy of four Toby Flood penalties to three from Chris Paterson when Tom Croft came off the bench to score what appeared to be the decisive try.
Scotland were defiant to the last and teed up an exciting finale with a brilliant individual effort from the wing Max Evans but Jonny Wilkinson closed out England's victory with a late penalty.
England captain Mike Tindall, who was replaced at half-time because of an ankle injury, hobbled up the Twickenham steps to collect the Calcutta Cup from his future mother-in-law, HRH the Princess Royal.
England's success has been built on consistency of selection: only 16 players have been used in the starting line-up all tournament.
But it was their bench today that made the difference, with Croft scoring on his return to international action after recovering from the fractured shoulder suffered in the autumn.
And they needed his intervention to settle a ferocious but error-strewn game.
Neither side was able to exert control for a consistent period.
With the ball in hand, Scotland were the more creative side early on with Ruaridh Jackson threatening at fly-half and Evans a thorn in the English side.
Scotland struggled in the set-piece. They lost their first three lineouts and were penalised three times in the scrum, which gifted England all their first-half points.
What the Scotland forwards did do well was compete at the breakdown and the visitors defended with ferocity - Kelly Brown and Richie Gray were to the fore - and quick line-speed to keep England shackled.
Paterson kicked Scotland into an early lead and it could have been better still had Rory Lawson managed to hold onto an offload from Brown with an open field in front of him.
England's scrum shoved Scotland back on half-way to earn Flood a simple shot at goal but the England fly-half pulled it wide, only his second miss of the championship.
Flood slotted his second attempt when Scotland prop Moray Low was penalised for illegal binding but in the loose England's play was ragged and undermined by careless errors.
Scotland counter-attacked from a knock-on and went through 14 phases, with Brown and Evans to the fore, before referee Romain Poite penalised England for offside and Paterson landed the kick.
It was a scrappy game all round, with little fluid rugby on show although England began to find their stride when Ben Youngs was able to bring Chris Ashton and Mark Cueto into the game.
Shontayne Hape and James Haskell both carried strongly as England began to build momentum but when Flood made a half-break Tom Palmer was wrongly penalised for a knock-on.
Flood did edge England ahead after another immense shove from his scrum but Scotland finished the half on top after snatching another turnover and drew level at 9-9 with a 39-metre drop-goal from Jackson.
Tindall was replaced at the interval by Matt Banahan, who was straight into the action with a powerful run through Brown to spark the best attack of the game.
Nick Easter offloaded to Ashton, who carved through the first ranks of Scottish defence before passing off the ground to Flood. Palmer, Dylan Hartley and Tom Wood all drove for the line but Scotland's defence scrambled well.
Brown was stretchered out of the game but Scotland's defence remained strong as England came again, although they were helped by more Red Rose mistakes.
Foden slipped the offload to Ashton, who responded to a call from Cueto by trying to chip the ball in-field but he managed only to slice it into touch.
Scotland changed their half-back after 54 minutes with Dan Parks and Mike Blair sent on, while England replaced Youngs with Danny Care.
Banahan thundered through the middle again as England moved to within five metres of the line when Scotland flanker John Barclay was penalised for hands in the ruck and sin-binned.
Flood nudged England back into the lead before Scotland built up a head of steam, only for referee Poite to call a halt to the attack after injuring himself.
Scotland coach Andy Robinson was furious.
When play resumed, Parks scuffed a drop-goal effort and the pressure was released, with Haskell then galloping downfield.
Ashton sent Foden racing clear down the touchline. The Northampton full-back was arrowing in on the corner only for Paterson to produce a magnificent try-saving tackle.
England sent on a quartet of huge experience in Steve Thompson, Simon Shaw, Wilkinson and Croft and eventually worked the breakthrough in the final seconds of the Barclay sin-binning.
Wilkinson and Foden combined down the right before England moved play left and Cueto offloaded for Croft, who crashed over Parks' tackle to score.
Scotland responded valiantly. England repelled phase after phase, with Wilkinson leading the tackling effort, before Evans reclaimed his own chip to score and tee up a thrilling finish.
But Wilkinson sealed the victory with a penalty.
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