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England edged to the brink of a first RBS 6 Nations title for five years with a 25-21 victory over Wales but were forced to survive a late fightback that evoked memories of the final-quarter collapse against their old rival at last autumn's World Cup.
Eddie Jones' men led 19-0 and 25-7 during the second half through an Anthony Watson try and the boot of Owen Farrell, who kicked six penalties and one conversion, but their defence fell apart in a dramatic finish.
Adding to Dan Biggar's earlier touch down, George North and Toby Faletau crossed in the final six minutes to send ripples of panic through the Twickenham stands before one final Welsh assault down the left touchline was successfully repelled. Both tries were scored while Dan Cole was in the sin-bin.
If Scotland topple France on Sunday, England will be crowned champions with a round to spare - the first time that has been achieved - and will march on Paris next weekend with the Grand Slam in their sights.
Even if the French storm Murrayfield and prolong the Championship to the final day, their vastly inferior points difference leaves them facing an impossible task.
English confidence will have grown after a win that offers partial redemption for the loss to Warren Gatland's team in September, a result that initiated England's World Cup exit and that still left a lingering sense of foreboding when Wales threatened another unlikely comeback.
Maro Itoje was outstanding in only his second start and third Test appearance, stealing opposition line-out, poaching ball and even making the break that led to Watson's try and the 21-year-old finished as man of the match.
Itoje received strong support from a fine England cast including Ben Youngs and Jack Nowell, but the late collapse will concern Jones despite the Australian seeing his players lift the Triple Crown.
Worrying scenes interrupted the third quarter when Wales captain Sam Warburton required several minutes of medical attention he was driven from pitch on the medical cart with his neck in a brace, in the process signalling to crowd he was conscious.
It was successful return to Test duty for Craig Joubert, who played his role in fast-paced game on his return to Twickenham - where he sprinted down the tunnel after awarding Australia an erroneous penalty which cost Scotland victory in the World Cup quarter-final.
The scrum had been the focus of the pre-match mind games with the rival camps seeking to influence Joubert by accusing the other of illegal technique, but the set-piece proved controversy-free all afternoon.
There were no early dramas at an early Welsh put in, but there was plenty of action in an exhilarating start by England that saw Dylan Hartley produce a terrific offload before Youngs was denied a try because of a knock-on.
George Ford took the wrong option as England pressed once more - the Bath fly-half had endured a poor start to the game - but the pressure was building and when Wales infringed Farrell was off the mark.
Turning to back rows James Haskell and Billy Vunipola to make ground and with Youngs sniping cleverly around the fringes, only desperate late defence from Rob Evans and Gareth Davies prevented Dan Cole from scoring.
The Welsh scrum buckled and Farrell was on target and when Dan Lydiate was penalised for not releasing and the lead had been extended to nine points as the first quarter passed.
England's onslaught continued with Wales denied the chance to gain any kind of foothold in the game and after 30 minutes the only fault that could be levelled was that the score hailed to reflect the home dominance.
That changed quickly, however, when quick ball allowed Itoje to evade two feeble tackles before Brown drew Liam Williams and sent Watson over for his 10th try in 19 internationals.
Finally Wales hauled themselves into contention with Jamie Roberts determined to make something happen.
The half-time talk in the Welsh dressing room made little impact as runs from Brown and Nowell swept Jones' men into the 22 before the attack ended with a penalty by Farrell.
When Wales won a penalty under the posts, they had little option but to signal for the scrum so great was the deficit.
After minutes spent searching for the breakthrough they claimed their prize, Ford taking too long over a routine clearance, Biggar charging down to score and then converting his own try.
The Welsh revival continued and Twickenham fell silent for a spell, but with Farrell adding two penalties in quick succession they had pulled ahead 25-7.
Cole was sent to the sin-bin for collapsing a maul, but in the same incident the Leicester tighthead winced in pain after receiving a palm in the eyes from replacement prop Thomas Francis so the penalty was reversed and England were able to clear their lines.
North went over for a try after Liam Williams offloaded in the tackle to Jonathan Davies and when Faletau crossed, Wales had two and a half minutes to the rescue the game but they had run out of time.