Andrew Samson
BBC Test Match Special statistician

Karun Nair made 108 off 78 balls after tea.

It's his third Test innings, which is the earliest anyone has made a triple hundred in their Test career - Len Hutton did it in his ninth.

Ishant Sharma takes the new ball, his flowing locks tied in a bun. He's only up around 81mph but the ball is shining like a glacier cherry under the lights and one beats Cook outside the off stump. Jake Ball is padded up as the nightwatchman looking on nervously as if he's awaiting an important job interview.

Alex Elliot: This Nair bloke what's his average Alex? About 10. What is he on Alex? 300 Typical #cricket, external at work question.

Lamda Pi: When was the last time a batsman scored a triple century with a Test average of 8.5? 

So England will have a maximum of five overs to negotiate under the lights this evening, although we have to stop in 17 minutes. The tourists will begin 282 behind, and have been bowled out for less than that four times in the series so far. 

India's highest in Test cricket and the highest England have ever conceded. Only 75 balls needed for Karun to go from 200-300.

Geoffrey Boycott
Ex-England batsman on BBC Test Match Special

You don't know where to field, there were six fielders on the boundary at one stage.

Liam: I can't take this ANYMORE.......HELP..... 

Hugo Walford: Extraordinary innings. Hats off to the young man.

300 for Karunpublished at 11:04 Greenwich Mean Time 19 December 2016

11:04 GMT 19 December 2016

Ind 759-7d (lead by 282)

Karun cuts Rashid to the boundary and reaches triple figures from 381 balls. That will be the declaration. He's the 26th player to achieve the feat in Test cricket and the exhausted England captain Cook sportingly shakes his hand. Kohli still has his t-shirt on, clearly that is not an indication of when he is going to declare. Coach Anil Kumble has taken a snap of the occasion for his own collection. 

Image source, Reuters

It doesn't come with this one. Dawson fires one down the leg side, Karun cannot make contact and the crowd falls silent for a moment.

Robert Stow: Classic England anyway, letting a guy who had a Test batting average of 8.5 close in on a triple century.

Al Watson: Can't work out if cricket on these sorts of pitches is boring or just a masterclass in batting.

The camera lenses have multiplied on the boundary's edge, they have appeared out of nowhere, like racer snakes, but just the two singles to Karun in the Rashid over and he still needs three more for his 300. The cavalier Jadeja reaches fifty from 52 balls and twirls his bat in theatrical fashion. 

Image source, AP

Mitesh Damji, London: Agree with comment from Nigel. You have to give credit to India and Kohli for the way they have played this whole series regardless of turning wickets or not. England should be learning and am sure they will in turn for ashes. There is say, if you can't beat them, join them!

Ind 747-6published at 10:52 Greenwich Mean Time 19 December 2016

10:52 GMT 19 December 2016

270 ahead

Jadeja down the ground to Moeen and it has gone into the second tier, the late golf commentator Dave Marr used to say: 'I don't go that far to look for my kids'. The left-hander pinches a single from the final ball and Moeen is only 10 short of a double century of his own.

India's highest Test total and there's a mis-field from Joe Root, I don't think he's ever gone so long without smiling. Two more fours to the merciless Karun, who has now struck 31, in addition to four sixes, and he's six away from the triple.

Vic Marks
Ex-England spinner on BBC Test Match Special

There's a chance that Rashid could pick up his 24th wicket of the series, but that statistic is starting to flatter him a little as he's often picked up wickets at the end of an innings like this, when he's gone for a few.

Karun will retain the strike after getting a run of Moeen when the ball had gone only a few feet away from him, as the excitable Bairstow flicked the ball at the stumps to allow an overthrow. Karun needs 20 to reach the triple.

Jonathan Agnew
BBC Test Match Special

We've got another 12th man coming on with some fresh bats and a message, which Mr Erasmus won't like. He's keeping them under close observation.

Karun must have been given a set time or number of overs to get his 300. If India needed to win this game, they'd have pulled out by now.

Ind 717-6published at 185 overs

185 overs

Karun 276, Jadeja 37

Are they going to let Karun get his triple century? He won't mind if Rashid is still bowling because a long hop is pulled away for six and two more fours follow into the leg side. The fourth hundred partnership of the innings and this one has taken just 85 balls.

Vic Marks
Ex-England spinner on BBC Test Match Special

I saw Keaton Jennings taking his shin pads off there. Quite sensible, as I don't think England will be using a forward short leg after this.