Postpublished at 18:21 British Summer Time 25 September 2020
And that's where we'll leave it for today.
Adam's report will be up on the BBC Sport website and app shortly.
And we'll be back in the morning for day four. Hope to see you then.
Essex close on 271-6 as Somerset fight back after tea
Essex opener Cook out for brilliant 172
Somerset made 301 all out in first innings
Team with best first-innings score wins trophy if game drawn
Gary Smee
And that's where we'll leave it for today.
Adam's report will be up on the BBC Sport website and app shortly.
And we'll be back in the morning for day four. Hope to see you then.
Somerset 301 v Essex 271-6
And even if Essex do sneak into a first-innings advantage, it sets up the game nicely for the neutral because Somerset will have to come out and attack in their second innings.
Don't forget, if it's a draw, the side with the best first-innings score lifts the trophy.
Somerset 301 v Essex 271-6
Jamie Porter defends the rest of Lewis Gregory's over and that's stumps.
And what an entertaining day it's been.
Alastair Cook's magnificent 172 was ended late in the final session as Somerset took five wickets after tea.
They might concede a first-innings lead yet, but they're still right in this game.
Porter 5, Wheater 0
Jamie Porter edges Lewis Gregory's first delivery low past the slips and down to the fence.
Four crucial runs as the deficit is reduced to 30.
Porter 1, Wheater 0
Adam Wheater is now solid in defence and confident leaving the ball as Craig Overton bowls a maiden.
Lewis Gregory will bowl the last over of a fascinating third day...
Gregory 19-3-54-4
Jamie Porter sees out Lewis Gregory's 19th over. Gregory has four wickets today and has been Somerset's star man.
Two overs to go tonight.
Porter 1, Wheater 0
Jamie Porter gets off nought with a poke behind point.
Three overs remain tonight. Can Somerset nip out another as the sun sets on Lord's?
Porter 0, Wheater 0
Adam Wheater comes in at eight.
Essex are still 35 behind. Somerset could well end up with a first-innings lead now you know! Madness.
Varun Chopra
Essex batsman on BBC 5 Radio Live Sports Extra
It's a special knock from Alastair Cook, he has single handily lead this Essex reply to Somerset's 300.
He's batted beautifully with some exquisite cover driving.
When he's playing so straight and balanced he is a hard man to dismiss but Lewis Gregory has bowled that well and it's a very good catch from Craig Overton.
Cook c Overton b Gregory 172 (Essex 266-6)
Alastair Cook's gone now!
This is an incredible finish to day three. Cook fends Lewis Gregory to Craig Overton at second slip and the big man takes a sharp grab low down.
It ends a fantastic innings of 172 - 383 minutes, 289 balls and 26 fours.
Cook 170, Porter 0
Wicket-maiden for Craig Overton. Just what the doctor ordered for Somerset.
Another wicket or two in the remaining five overs tonight would make things VERY interesting!
Essex still trail by 37.
Cook 170, Porter 0
Jamie Porter comes in as nightwatchman for Essex.
Varun Chopra
Essex batsman on BBC 5 Radio Live Sports Extra
Height was perhaps a factor which may have gone for him, the umpire had no doubt and it was a swift decision.
Well deserved for Craig Overton.
ten Doeschate lbw b Overton 21 (Essex 264-5)
Hello!
Craig Overton goes full and it's bang on the money. It hits Ryan ten Doeschate on the pad and up goes the finger without hesitation.
Essex still trail by 37. Can Somerset claim a remarkable and crucial first-innings lead?
Cook 170, ten Doeschate 21
No alarms for Essex as Lewis Gregory takes the new ball from the Pavilion End.
Just the single off the bat of Ryan ten Doeschate.
Cook 170, ten Doeschate 20
Craig Overton comes back well after conceding a boundary from the first delivery, but Essex still manage a couple of singles.
Ryan ten Doeschate was just the man Essex needed to come in after that wobble straight after tea. The 40-year-old is up to 20 and his stand with Alastair Cook worth 55.
Varun Chopra
Essex batsman on BBC 5 Radio Live Sports Extra
A key half hour coming up for both sides.
Somerset realistically know that they are going to lose on the first innings total, it's going to take something really dramatic to bowl out this Essex side.
So, they'll be thinking that this new ball has got to do some damage.
Cook 169, ten Doeschate 19
Alastair Cook guides Craig Overton's wayward first delivery with the new ball down to the fine-leg boundary.
Essex are 40 shy of Somerset's first-innings total.
Tweet using #bbccricket
Louise Graham: If this game is a draw there should be a super session.
Herb Acius: Such a lot to like about Josh Davey - no fuss, no strops, just runs in all day and puts it on a length - what a pro.
Ryan Hemmings: When’s the new ball available? From a desperate Somerset fan.
Right now Ryan!
Somerset 301 v Essex 257-4
Of course they will take it. Craig Overton is back.