Straight drives are working well today - here's Cook picking up a boundary with one earlier this morning.

Westley drives extravagantly at Morkel but misses, clipping his own pad as the ball bounds through to the keeper. Ooh, that's better. Four! An angled drive goes firing past Cook at the opposite end, and Cook turns to watch the ball thud into the rope. That breaks a string of maidens from Morkel, but the big fella keeps pushing the ball across Westley to make sure he doesn't nab any further runs.

Graeme Smith
Ex-South Africa captain on BBC Test Match Special

It's going to be a heavy old day on the legs for the bowlers, with this damp outfield. Faf du Plessis will have to be smart on how he uses them.

Time for a change of pace. Here's left-arm spinner Keshav Maharaj, coming over the wicket to Cook, and Cook pushes up towards mid-wicket as he gets his eye in. There's very little width on offer from Maharaj as he trots in, aiming for the rough that's started to show just in front of Cook. A maiden to begin with.

Stephan Shemilt
BBC Sport at Old Trafford

As Keaton Jennings fails again, Haseeb Hameed has a hit with England batting coach Mark Ramprakash.

I'm a bit torn about Jennings. He's out of nick, yeah, but I thought he did well in the second dig at The Oval and he strikes me as one of those players - like Colly - who will drag themselves back into form in whatever way they can. But with the Ashes around the corner... Mitch Starc and Josh Hazlewood would love to have a bowl at him. Morkel, who has magnificent figures so far, continues, and Westley sways under a nice bouncer. Morkel beats him with the final ball of the over, a corker outside off stump.

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John Kirriemuir‏: Daryl Mitchell (Worcs opener) has experience - 11k first class runs - and form, averaging 50 this season. Also superb catcher.

Nick‏: Hameed did well in tough conditions in India, and just got a century for Lancs. Has to be better option than Jennings.

Chris Pinkney: SA & India are tough baptisms of fire. Stick with him for WI, if he fails, then it's time to move on.

Duanne Olivier will continue, pushing the ball across Tom Westley, who leaves anything he can. That's lovely though, some late swing as Westley pushes foward, and the ball zips just past the outside edge and into Quinton de Kock's gloves. Olivier grins at the batsman but loses his run up as another gust of Manchester wind comes across the ground.

Those clouds...

Those red postboxes...

It could only be one cricket ground in the country.

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Morne's keeping his jumper on now. The Old Trafford flag is furiously fluttering above the pavilion, and the wind puts Morkel off as he pulls out of his run-up and tries again. Cook waits, bat hovering, before he prods the ball back towards the bowler. A maiden. Meanwhile, behind the stands, Haseeb Hameed is having a net...

Drinks are over and done, and now Morne Morkel is going to bowl from the James Anderson End. I imagine, after a few beers, that could be a tad confusing for the Old Trafford crowd.

The first hour is done, which means it's time for drinks. Here's the first and only wicket to fall, with Keaton Jennings caught behind for 17.

Olivier continues, and Cook straight drives to perfection for four. Olivier is better when he swings the ball, and he bowls a nice, fuller line to Cook that squares up the England opener. A little flick off the hip brings Westley on strike, and Olivier spends a bit of time shining the ball before he swings the ball well wide of Westley.

Geoffrey Boycott
Ex-England batsman on BBC Test Match Special

We haven't seen the best of Rabada yet in this series. He hasn't bowled very well since being suspended. He's bowling too many balls down the leg side to the left-handers. He's better than that. He's a quality bowler, with a fine technique and physique.

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I like Westley a lot. I've seen quite a bit of him at Essex. And I'm a big fan of anyone who wears the cable knit jumper while they're batting. This is a little too wide from Rabada and it's easy enough for Westley to raise his arms and let the ball go through to the keeper. That's superb from the bowler though, squaring Westley up, and the ball pops up off his thigh pad and in front of a diving Amla. The final ball is even better - full, straight, and Westley just about avoids inside-edging onto his stumps. Lovely stuff.

Right, folks. Talk to me about Keaton Jennings. Stick or twist? Should England keep their faith in a man who scored a century just five Tests ago? Or is it time for a change? Who could take his spot?

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That was nice from Olivier to dismiss Jennings. It was a good length delivery and given how skittery Jennings has been with those off-stump deliveries, he knew he'd have a tickle at it. Tom Westley is in at three, and is promptly beaten as he goes forward to defend. Olivier bends his back and chucks down a bouncer that Westley ducks under, before the Essex man clips a single off his pads to get going.

Geoffrey Boycott
Ex-England batsman on BBC Test Match Special

Full marks to the bowler - he drew him forward with a good ball, it left the batsman and he nicked it. Keaton Jennings hasn't convinced me with his technique. He needs work. He can't do it in the nets before a Test match, it takes time. He'll have to correct something he's been doing for 15-20 years. He can do it, but it needs somebody to take hold of him and help him.

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