South Africa reviewpublished at 27.4 overs
Ryan Rickelton, who has a curious open stance, is smacked on the pads by Stuart Broad.
The umpire gives it out - but South Africa opt to review.
Bad light stops play with England 97-0, needing 33 more for a 2-1 series win
Crawley unbeaten on 57, Lees on 32 not out
South Africa slip from 83-1 to 169 all out - Stokes 3-39, Broad 3-45
England earlier lose three wickets for four runs to be dismissed for 158
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Tom Rostance, Tom Mallows and Ffion Wynne
Ryan Rickelton, who has a curious open stance, is smacked on the pads by Stuart Broad.
The umpire gives it out - but South Africa opt to review.
Isa Guha
Former England bowler on BBC Test Match Special
There's a lot of cloud cover and humidity in the air just now, this is an important phase of the game. Rickelton gets himself into such an unusual position.
Vernon Philander
Former South Africa bowler on BBC Test Match Special
England will feel they have a window of opportunity here with two new batters in. South Africa were looking for captain Dean Elgar to steady the ship and build an innings this afternoon.
A brilliant over from James Anderson yields no reward. He tries a couple of outswingers, then an inswinger, with final ball whistling past the outside edge of Khaya Zondo's bat.
Zondo has been very watchful so far. He is yet to score off his first nine deliveries.
Here is the delivery from Stuart Broad that did for Dean Elgar.
Everyone was convinced it was out - including Elgar - but a review would have seen the decision overturned.
Good shot from left-hander Ryan Rickelton as he seizes onto a wide delivery from Stuart Broad and cracks the ball through the covers.
It was uppish but in the gap so never in danger of finding a fielder.
James Anderson goes full to new batter Khaya Zondo and another thickish edge falls just short of the slip cordon.
The crowd are expectant now.
Alex Hartley
Former England bowler on BBC Test Match Special
You almost get the sense now this is a real opening for England, South Africa do have a long tail. What a fantastic catch from Ollie Pope.
Jonathan Agnew
BBC cricket correspondent on Test Match Special
Is this the start of it I wonder? There is a soft middle order to South Africa. The lead is 51.
Petersen c Pope b Anderson 23 (SA 91-3)
That's a brilliant catch by Ollie Pope! James Anderson tempts Keegan Petersen into pushing at a delivery outside off stump and the ball races to Pope at fourth slip, who takes a brilliant diving catch low to his left.
It is amazing how a wicket can suddenly shift the momentum.
Keegan Petersen, who had looked so composed, is squared up by Stuart Broad but the leading edge falls safely.
This match is wonderfully poised.
Keegan Petersen has impressed so far this afternoon. Here he is hitting Stuart Broad for two fours in the first over after lunch.
Jonathan Agnew
BBC cricket correspondent on Test Match Special
It's another very strange incident in this fast-flowing game. Incredible. That was hitting fourth stump.
Alex Hartley
Former England bowler on BBC Test Match Special
The thing that got me is Dean Elgar walked off before it was even given, he must have felt so out. He will be furious with himself when he sees that back. That shows the importance of checking your guard, just to make sure you know where you are standing.
Keegan Petersen has looked in really good touch so far. James Anderson just strays towards leg and Petersen is on it in a flash, working the ball through mid-wicket for three.
Daniel Norcross called it. We have just seen a ball tracking replay which showed the ball was missing leg stump.
South Africa still have all three reviews left as well. A potentially costly error by Dean Elgar.
Daniel Norcross
BBC Test Match Special
I think that was well worth a review from Dean Elgar.
Alex Hartley
Former England bowler on BBC Test Match Special
The captain Elgar walked off before the umpire had even raised the finger! It was a lot fuller from Broad, possibly clipping leg stump. He felt he was stone dead and walked off...
Elgar lbw b Broad 36 (SA 83-2)
Third time's a charm! Stuart Broad beats Dean Elgar's defences again, the ball smacks into the pads and this time Nitin Menon doesn't hesitate putting the finger up.
Dean Elgar doesn't hesitate either. He began walking before the umpire made a decision.
A vital breakthrough for England.