Williamson sweeps behind square for four but Leach nearly does for him last ball.

A slow, loopy delivery grips and turns with Williamson just withdrawing his bat in time after being tempted into playing.

Great to hear from the comedian Mick Ferry!

As well as Williamson has played, I do agree that any suggestion he has made this game safe for New Zealand are more than a little premature.

Image source, Getty Images

Mick Ferry: Well done Williamson. Great century and listening to Kiwi commentators, you’ve saved this Test apparently.

The off side field is packed but Williamson still manages to thread the ball through for another boundary. Lovely shot.

Not long to go until tea now. Maybe time for two more overs. Can England prevent it from being another wicketless session?

Leach is sticking determinedly to bowling outside leg. Blundell seems adamant he won't go after it.

Another maiden. Who will blink first?

Image source, Getty Images

Kane Williamson brought his century up off 226 balls, although it's not even his slowest against England. Williamson's knock in the second Test at Hamilton in 2019 took 231 balls.

Right back to it for Williamson. He still has a job to do for New Zealand.

Having looked beaten after day two, he'll be trying to plot their way to victory as we approach tea on day four.

This is Kane Williamson's fourth Test century against England, and his third against them on home soil. His top score against England was the 132 he made at Lord's in May 2015.

100 for Kane Williamsonpublished at 135.1 overs

135.1 overs

NZ 409-5

A 26th Test century for Kane Williamson! He's back in form just when New Zealand needed it.

A typically calm and composed knock, he reaches three figures from 226 balls.

Cut away for four to reach the milestone after making us all wait for a while!

Another change of tactics from England. Leach is now bowling over the wicket and into what little rough there is outside Blundell's leg stump.

The right-hander isn't interested in engaging. He pads up to the majority before blocking the last, straighter delivery. Maiden.

Broad hangs the ball wide outside off to tempt Blundell into a drive, the Kiwi batter takes the bait and swishes at it. Close but no edge.

After a couple of drives into the covers, Blundell gets a single by opening the face and hitting over slip to deep third.

Williamson then plays out a couple more dot balls. He's still on 99.

Williamson is in no rush. With the New Zealand players on the balcony on the edge of their seats, he plays out a maiden from Leach.

He's done everything at his own pace in this innings.

Blundell nails a cover drive for four to take New Zealand past 400. The lead is now 178 - at what stage do England start to worry?

Given how well this pitch is playing, I'd say not just yet.

Meanwhile, a good stop from Stokes keeps Williamson to a single. He's on strike for the next over on 99...

Tom Blundell unfurls another of those glorious cover drives as he takes Stuart Broad for back-to-back boundaries. A delicious shot.

Image source, Getty Images

It's a late one ahead of the start of a new week, so doubtless a few of you are starting to consider hitting the hay as we meander into the early hours of the morning. Rest assured you can keep up to date with all the goings on from the Basin Reserve in Wellington using the BBC Sport app.

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50 for Tom Blundellpublished at 131.1 overs

131.1 overs

NZ 398-5

Broad is back and Tom Blundell edges his first ball wide of slip and down to deep third for a boundary that takes him to his half-century.

A crucial knock for his side. It also brings up the 100 partnership with Williamson for the sixth wicket.

Kane Williamson has a long hard look at big turning delivery from Jack Leach at the end of the last over. He is two runs away from a Test century

Tom Blundell, meanwhile, is the same number of runs away from a half century. This partnership is worth 97.

Stuart Broad to continue.