Comment: Vaughan attracts more pressure

South Africa have not won a Test series in England since they were readmitted to the international circuit, despite having their noses in front on all three previous tours here. Somehow, you feel they are not going to blow their chance this time.

One up, with only the Oval to come after this match, they have England on the ropes here, with a second consecutive handsome victory beckoning after the frailties of the home side's top order were exposed again in a succession of calamities.

Alastair Cook and Ian Bell have both brought about their own downfalls with poor shots, maybe Michael Vaughan as well, although it took a good, low catch by Hashim Amla, diving at extra cover, to give Andre Nel his wicket for the second time in the match. Only Andrew Strauss can argue that he got a decent ball.

Unless Paul Collingwood can produce some measure of evidence that he is worth his place in the side, it is all down to Kevin Pietersen to give England any semblance of a chance. So far, so good - but he will have to turn what he has so far into something significantly substantial in the final session.

Vaughan will be willing him to do so, while knowing that his own failure only increases the pressure on him as captain. He made a decent enough start, picking the bad balls early on to help himself to four boundaries. And the shot that got him out? Okay, had Amla not moved so swiftly to take the catch, had the shot been a couple of inches wider, it would have been four all the way. On the other hand, the delivery from the excitable Nel was shorter and more wide of off stump than Vaughan anticipated and, stretching, he gave the drive just a little too much air.

Safe to say that Cook and Bell, however, will not be getting the benefit of any generous analysis. Cook, shaping to pull Makhaya Ntini, seemed almost to give up on the stroke when he realised the ball was not really there for it, top-edging hugely. Mark Boucher showed terrific judgment and movement to get under it, but it was a rank shot.

Similarly Bell, likewise faced with a short ball outside off stump from Ntini and perishing in much the same manner as he unwisely went for the hook.

A tea score of 126-4 is really 43-4 when you take off South Africa's first innings lead. We're not expecting to be here on Sunday - and maybe not for long tomorrow.