Daniel Norcross
BBC Test Match Special

Now Ben Foakes has got to his hundred there's no need to dig in. Not sure England will declare conventionally as such, just keep swinging for this ninth wicket until it falls then that will be then they go in.

Ben Foakes and Jack Leach make hay with a series of singles off Lungi Ngidi.

Here's how Ben Foakes reached his second Test century.

Andy Zaltzman
BBC Test Match Special statistician

Ben Foakes has done something that no England wicketkeeper has done in 117 Tests. He has scored a century after keeping wicket. All the other centuries have been batting first. Matt Prior was the last to do it at in Auckland 2013.

Jack LEACH!

Leach whips out a reverse sweep and with a technique known only to him, somehow manages to smack the ball over extra cover for four. Shot!

Daniel Norcross
BBC Test Match Special

His bat was on the line just before the stumps were broken.

That is an excellent stretch from Ben Foakes, who had come dancing down the pitch.

As you were.

Now then, has Foakes been stumped?

I think he's managed to dive home, but we're going upstairs.

Ben Foakes goes for a big strike down the ground off Keshav Maharaj and somehow manages to avoid two fielders, with the ball trickling to a halt before the boundary rope.

A great day for anyone called Ben.

Ben Lovett: A double Ben century, on my birthday. Lovely stuff for the Ben community.

Oh, Jack Leach! That'll be four! A hearty swing of the bat and a thick outside edge brings up 400 for England.

Leach is promptly beaten by the ball of Ngidi's over.

Piemontemio: I'm with Bob Hawkins (17:11) - why declare? I can't see where 400 for South Africa is coming from, so just keep batting to make our last innings run-chase a formality...

Avirup Chaudhuri: Has an England innings ever before featured centuries by players with rhyming surnames?

Lungi Ngidi will replace Anrich Nortje.

Jack Leach sees out the remainder of Keshav Maharaj's over.

Vernon Philander
Former South Africa bowler on BBC Test Match Special

South Africa will be keeping an eye on overs left this evening. There's about an hour left and there's nothing worse as an opener in the field waiting to bat like this.

Jack Leach is coming out to join Ben Foakes.

James Anderson, meanwhile, hasn't got his batting gear on. He's actually doing a crossword with Joe Root. Real father and son vibes.

Simon Mann
BBC Test Match Special

A shake of the head from Ollie Robinson. We might not need a declaration.

Vernon Philander
Former South Africa bowler on BBC Test Match Special

It's been a phenomenal effort from Foakes when his team needed it. He's managed to steer England clear of any sort of danger.

Having been frustrated a couple of balls earlier, Foakes took full advantage of the short, wide ball.