Another Flood penalty nudged England in front in the second half but Scotland proved frustrating opposition for Martin Johnson's men.

After replacement Tom Croft's try looked to have sealed the win with 13 minutes to go Scotland hit straight back through Max Evans' score before Jonny Wilkinson's late penalty secured a nervy victory.

With a two-point advantage and vastly superior points difference over second-place Wales, only an unlikely sequence of results in the final round - in which England travel to Ireland and Wales to France - would prevent a first Red Rose title in eight years.

After a Saturday which defied Six Nations convention when Italy secured a first defeat of France in Rome and Wales pulling off a rare home defeat of Ireland, there were plenty of positive omens for Scotland at Twickenham - a venue they had not won at since 1983.

And they were rewarded for a bright start with a Paterson penalty on three minutes after referee Roman Poite penalised England for going in off their feet.

But England gained an early ascendancy at the scrum and after missing one shot at goal, Flood made no mistake with his second attempt closer in after the Scotland front row had engaged too quickly.

Paterson and Flood exchanged further penalties but England were struggling to fire as an attacking force with Scotland's tenacious backrow forcing a number of turnovers to nullify the likes of Chris Ashton.

Despite England's relative inexperience in the front row - their cumulative caps were almost a third of Scotland's - Poite was consistently ruling in their favour and a 31st minute Flood penalty put them in the lead for the first time.

Right on the stroke of halftime, Scotland gained some territory in the English 22 thanks to a clever kick from Rory Lawson and Jackson dropped into the pocket to stroke over a drop goal.

Martin Johnson opted to introduce Matt Banahan for captain Mike Tindall at halftime and one of the Bath powerhouse's first acts was to smash into Scotland No.8 Kelly Brown to lay a platform for an England attack.

While flanker Tom Wood was hauled down just short of the line after England flew downfield, Brown had to be removed from the fray on a stretcher to be replaced by Richie Vernon.

The visitors' cause was not helped when John Barclay was yellow carded for an infringement inside the Scottish 22 and Flood nudged England in front on 57 minutes, although the sinbinning proved to be one of Poite's last acts before picking up a calf injury which forced him to be replaced by Andrew Small.

England so nearly made the most of their one-man advantage as James Haskell and Ashton race down the left-hand side only for Paterson to pull off a fabulous try-saving tackle on opposite number Ben Foden.

But it was only once Barclay was back on the field that England finally made the breakthrough when England spread the ball quickly from right to left and Mark Cueto found Croft who hurdled his way over Dan Parks to touch down. Wilkinson converted to take England 19-9 ahead.

Just when Twickenham was breathing a sigh of relief, Scotland struck back with just six minutes remaining.

Nothing looked on as Scotland worked their way in the 22 but Evans chipped over a static defence to gather and touch down.

Paterson's conversion brought the visitors back to within three points only for Wilkinson - one of the few survivors from England's last Grand Slam in 2003 - to strike over a penalty with two minutes remaining.

Now only Ireland stand between England and a first clean sweep in eight years but Martin Johnson's men will need a far improved performance in Dublin.