Group 1: Durham v Essex; Warks v Notts; Worcs v Derbys
Group 2: Leics v Middlesex; Surrey v Glos
Group 3: Lancs v Yorks; Sussex v Northants
Middlesex 224-7 v Leicestershire
Luke Hollman goes!
Ed Barnes finally breaks his 90-run stand with John Simpson, clean bowling Hollman for 32.
Leicestershire needed that.
Sussex 175 v Northants 55-3
Three catches for Ben Brown, three wickets for Sussex.
Ricardo Vasconcelos is the latest to fall, edging behind off George Garton for 20.
Middlesex 218-6 v Leicestershire
That's John Simpson's half-century. He and Luke Hollman (28 not out) have shared 86 for the seventh wicket.
Warwickshire 212-3 v Nottinghamshire
Sam Hain reaches his half-century from 159 balls, including just three boundaries.
Warwickshire are batting themselves into a really strong position at Edgbaston.
Sussex 175 v Northants 43-2
What were we saying about good progress?
That has now been checked with the wicket of Luke Procter, who's dismissed for nine by Jamie Atkins. It's another catch for wicketkeeper Ben Brown too.
Yorkshire 159 v Lancashire 54-0
This has been some day so far for Lancashire - especially given they lost the toss.
Alex Davies continues to dominate the bowlers, now on 41 not out, while Keaton Jennings is on seven.
Sussex 175 v Northants 40-1
After losing Ben Curran early, Ricardo Vasconcelos (16 not out) and Luke Procter (nine not out) have settled any early Northants nerves as they reply to Sussex's 175.
Yorkshire 159 v Lancashire 41-0
Alex Davies looks like a man on a mission, punishing anything on his pads and anything wide with absolute authority.
Already he's struck six fours as Lancashire move to 41-0.
Middlesex 200-6 v Leicestershire
After those two wickets in two balls for Callum Parkinson, John Simpson (39 not out) and Luke Hollman (24 not out) have done well to steady Middlesex.
They've now put on 68 for the seventh wicket
Worcestershire 248-6 v Derbyshire
It's been a bit of a feature of this opening day that batsmen have got beyond fifty but failed to bring up three figures.
Brett D'Oliveira is the latest to suffer that fate, being dismissed by Fynn Hudson-Prentice for 71.
Yorkshire 159 v Lancashire 24-0
Alex Davies has played a couple of really nice strokes already here.
Lancashire move onto 24-0. To put that into context, Yorkshire were already six down by this point.
Surrey 216-5 v Gloucestershire
Jamie Overton's certainly not shy of playing some shots, the former Somerset all-rounder racing to 23 off 29 deliveries.
Hashim Amla remains on 67 and will be eyeing a 54th first-class century.
Yorkshire 159 v Lancashire 17-0
Unlike their opponents earlier today, Lancashire's innings has - so far - got off to a relatively comfortable start.
Alex Davies and Keaton Jennings have guided them to 17-0 at Old Trafford.
Warwickshire 173-3 Nottinghamshire
Warwickshire have gone along very nicely at Edgbaston today, thanks largely to Will Rhodes' 91.
Sam Hain (33 not out) and Matthew Lamb (five not out) are playing particularly patiently here - Hain's knock coming off 133 deliveries so far.
Essex 182 v Durham 1-1
Six wickets have now fallen for four runs across the two innings!
Jamie Porter strikes in the third over of Durham's reply, pinning Alex Lees in front for a seven-ball duck.
Sussex 175 v Northants 11-1
Sussex will be very keen for early wickets having made just 175 and they've got one in the fifth over.
Ben Curran is dismissed by Henry Crocombe, fresh from his unbeaten 46, and Northants are 11-1.
Yorkshire 159 v Lancashire 0-0
Keaton Jennings and Alex Davies are out to the middle ready to get Lancashire's reply in the Roses match under way.
Ben Coad has the new ball.
Worcestershire 229-5 v Derbyshire
Heartbreak for Jack Haynes!
Just three short of a maiden first-class century, the 20-year-old has been dismissed by Matthew Critchley.
His 187-ball knock included nine fours and one six.
Surrey 183-5 v Gloucestershire
Hashim Amla, predictably, remains the key wicket here but Gloucestershire continue to plug away really well.
Will Jacks is the latest man to fall, bowled by Ryan Higgins for 24, meaning Jamie Overton has joined Amla out in the middle.
Essex 182 v Durham
Nick Gledhill
BBC Radio Essex
Approaching tea here it appeared the story was likely to be Michael Pepper’s pending debut first-class century. Replacing Dan Lawrence he had played with great composure in making 92 but he was then trapped lbw by Chris Rushworth, who had been brought back into the attack with Durham needing a breakthrough.
They could not have anticipated a sensational collapse which saw Rushworth and Ben Raine claim the last five wickets in the space of 17 balls to draw Durham level with Essex in the table.
The champions now need an immediate response from their bowlers in a game they can’t afford to lose.