Compton's batting, erratic at times today, has settled down somewhat. Three easy runs off his legs off Piedt take him to 45 and England to 167-2. The tourists will be happy with this.

Image source, Reuters

Impressive from Rabada - he's got something about him, the youngster. Root is content to see out the rest of that over. Time for two more before tea, I suspect.

Geoffrey Boycott
Ex-England batsman on BBC Test Match Special

"He went to pull or hook but pulled out, the ball hit the bat and went straight up in the air but the slip couldn't get there and neither could the bowler. Lucky."

Image source, AP

What was I saying...? Rabada finds pace and bounce, Root is squared up and his bat is pointing straight up when the ball hits it. It loops a yard or so behind Root, and even AB de Villiers can't quite get there as he charges in from second slip and flings himself forward full length. Agonisingly close for South Africa.

 That spell from Morkel lasted only four overs, despite it containing a wicket and a dropped catch. Harsh captaincy. Piedt continues - and Root has to assert his authority and snub Compton's calls for a silly single. There's no doubt which England batsman is in charge out there. Ten minutes until tea. England's session so far.

Alex Hubbard: Blinked when Hales got out and when my eyes opened again Root was 21*

Image source, AFP

That Alex Hales wicket seems a while ago now, such has been Root's calming influence (that edged drive to Morris aside). Busy at the crease, alert between the wickets and even dominant with his calling, his batting exudes authority. As has been the case several times today, the returning Rabada wastes much good work in that over by slipping one down the leg side.

Dane Piedt's breather didn't last long - he's back on in place of Rabada. With only one fielder saving one on the leg side, it's easy pickings for the fleet-footed Root. Compton, possibly persuaded by a rare turner that defeats his cut stroke, follows suit by dancing down the pitch and playing with the spin. Think middle overs in one-day game and you get the idea.

Image source, Getty Images

Khael Malik: Compton is the Makelele of cricket. Efficient, dependable and leaves the fancy stuff to others. I hope I haven't jinxed him.

Mike Bryan-Jones: Compton everything you want from a number 3, won't allow wickets to fall in clusters and will always put the bad ball away

Morkel is South Africa's most experienced, threatening and best bowler, yet he has sent down the fewest overs today - this is his 12th. After banging away at his favoured back-of-a-length-outside-off-stump approach, he almost catches Compton out with a full one. Jonathan Trott Mk II survives - and has 41 to his name by the end of an over yielding two singles.

Image source, Getty Images

Morris is just describing to Faf du Plessis which part of his fingertips he managed to get on that Root chance. The very ends, judging by the replay. Meanwhile, Root scampers an all-run four off Rabada - after another uncharacteristic misfield.

Jonathan Agnew
BBC Test Match Special

"Dropped, and there was all sorts of a mix-up with the running there. That's poor cricket. It was a dreadful shot from Root."

Root dropped on 13published at 48 overs

48 overs

Eng 153-2

Image source, Getty Images

Ooooh! Nearly another absolute scorcher from Morris. The finer of two gullies, he leaps full length to his left but can only palm it round the post. It's such a good effort he even gets a pat on the bum from his colleagues. Apart from Morkel, the bowler. Root lives to fight another day after that rash drive - and Compton rubs salt into South African wounds with a leg glance for four to end the over.

Image source, Rex Features

Paceman Kagiso Rabada back into the attack, in place of off-spinner Dane Piedt. South Africa could do with another wicket here - they'll know that if Root gets in, he tends to stay in. An authoritative pull for four from the new man at the crease is ominous for the hosts. A misfield helps him take two more - he has 12 off 13 balls already.

Ben Silva: Shame De Villiers hasn't his wk gloves on, would have spilled that last Test!

Mickey Wallis: Incredibly frustrating. Just when you think Hales will go on he gets a peach. But at least Rooty's in! Think he'll go big today.