The England captain, who had scored only 23 runs in four innings previously in the series, was dismissed for 17 at Edgbaston as his side slipped to 39 for two having conceded an 83-run first-innings deficit on the third day.

Vaughan drove Andre Nel in the air towards extra cover and Hashim Amla made a brilliant diving catch to leave England's captain under pressure for his place and his side heading towards a series defeat.

Vaughan had walked out to the crease after Alastair Cook fell in the sixth over.

Cook attempted to pull Makhaya Ntini's second ball from outside off stump and sent the ball flying in the air to allow wicketkeeper Mark Boucher to take the catch at square leg.

The England skipper began nervously and a mix-up over a quick single almost resulted in Andrew Strauss being run out at the non-striker's end, but he recovered his composure to hit two boundaries off Ntini.

Just as he seemed to have weathered the nervous early stages of his innings, Vaughan's misjudgement with a front-foot drive forced him to take the long walk back to the dressing room and inevitable speculation about his future.

South Africa had resumed 25 runs ahead, on 256 for six, aiming to stretch their lead to beyond 100 and take a firm stranglehold on a series they already lead 1-0 following their 10-wicket victory at Headingley.

But it took just two overs for England to make a breakthrough, with left-arm seamer Ryan Sidebottom removing Ashwell Prince who pushed at a wide delivery outside off stump and edged behind.

England should have claimed another wicket in the next over with all-rounder Andrew Flintoff, the catalyst for yesterday's fightback, forcing Boucher into edging to Paul Collingwood at third slip but he was unable to take the catch despite diving one-handed.

It was a major blow to England, who had to wait another nine overs before they claimed the next breakthrough with Morne Morkel helping to forge a 29-run stand.

Morkel was perhaps unfortunate to be dismissed when he went to an lbw appeal from James Anderson.

Anderson's delivery had pitched clearly outside leg stump, and the decision continued umpire Aleem Dar's run of contentious decisions in the match.

Nel fell in the next over when Sidebottom swung the ball in and removed his middle stump, and that prompted Boucher to embark on a slogging campaign which saw him hit three boundaries in the Nottinghamshire seamer's next over.

Once again England's fielding let them down when Boucher hooked the last ball of the over from Sidebottom straight to Monty Panesar in the deep, and the bowler dropped the regulation catch.

Fortunately, the error was not as costly as it could have been, with Vaughan taking a diving catch at extra cover to end the innings and restrict South Africa's lead.

England's reply began nervously, with Cook fortunate to survive an lbw appeal from Nel before he had scored in the second over, with television replays suggesting the ball would have hit middle stump.

Cook and Strauss eased the pressure by both clipping off their legs in the next couple of overs to the delight of the rowdy Edgbaston crowd, who had already started taunting Nel.

But after captain Graeme Smith brought Ntini into the attack from the City End it brought immediate rewards, with Cook falling.