Derbyshire's Shan Masood makes second successive double century
Somerset's Tom Abell scores career-best 150 not out against Surrey
Keith Barker takes 6-53 for Hants v Kent and James Vince hits a 99-ball hundred
Michael Burgess hits second successive hundred for Warwickshire
Josh Bohannon scores hundred for Lancashire against Gloucestershire
In D2, Worcestershire's Brett D'Oliveira makes 169 not out against Sussex
John Simpson hits 104 not out as Middlesex build big lead against Glamorgan
Ben Slater and Lyndon James score hundreds for Notts against Durham
Hain c Wheater b Steketee 29 (Warwickshire 124-5 v Essex 168)
Champions Warwickshire lose their third wicket of the morning as Australian Mark Steketee finds enough movement off the seam to have Sam Hain caught behind.
A third slip is brought in for new batsman Michael Burgess but he is quickly under way with a cover drive for four.
Zaib c Duke b Revis 4 (Northants 85-5 v Yorks 296)
Saif Zaib only lasts six deliveries and Matt Revis strikes again.
A full delivery angled across the left-hander, Zaib leans a long way across to play when he should be leaving and feathers one behind.
Yorkshire right on top now.
Image source, Getty Images
Surrey v Somerset 330-8
A single at the start of a new James Taylor over takes Tom Abell to 150 off 292 balls. This is a career-best for the Somerset captain, surpassing his 135 against Lancashire at Old Trafford in 2016.
Durham 230 v Nottinghamshire 100-1
Dave Bracegirdle
BBC Radio Nottingham commentator
Nottinghamshire will now feel they’ve laid a platform for a sizeable first innings score after seeing off the threat of Chris Rushworth.
Ben Slater is starting to flow, having not scored in the opening 25 minutes of the day, but both he and Ben Duckett have taken toll already of the change bowlers.
George Drissell, on his Durham debut as a concussion sub for Liam Trevaskis, is about to enter the attack for the first time.
Leach c Burns b Taylor 6 (Surrey v Somerset 325-8)
Jack Leach hung around for 53 minutes but a leading edge off James Taylor has seen him caught at mid-off by Rory Burns.
Peter Siddle is the new Somerset batter in his 200th first-class match.
Young b Revis 33 (Northants 81-4 v Yorks 296)
A major blow for Yorkshire.
It had been four-and-a-half an over progress for Northants this morning with New Zealander Will Young going nicely.
But he's late in coming forward to defend and Matt Revis has scuttled one through the gap to send off stump flying.
Image source, Getty ImagesLancs 61-1 v Glos 252
Decent progress for Lancashire in the first hour of day two.
Luke Wells has driven impressively at Josh Shaw, whose two overs have disappeared for 18.
Josh Bohannon is alongside and the pair have a fifty stand for the second wicket.
Glamorgan 122 v Middlesex 217-7
John Simpson glances James Harris down to long leg for a single and reached a 122-ball fifty, which has included seven fours so far.
Middlesex are almost 100 ahead now, with Simpson and Toby Roland-Jones having added 103 before the latter fell to James Harris for 65.
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Leicestershire have their second wicket with Brooke Guest lbw to Will Davis and Derbyshire are now on 81-2.
Joe Leach has gone for 26 at New Road, but Brett D'Oliveira is now 114 not out in Worcestershire's 376-7 against Sussex.
Ben Slater has progressed to 37 not out for Notts, who are 90-1 in the 29th over after bowling Durham out yesterday for 230.
Toby Roland-Jones and John Simpson have now posted a 100 partnership for Middlesex, who are 213-6 against Glamorgan - Simpson is 48 not out and Roland-Jones has 65.
Surrey v Somerset 320-7
Tom Abell is still going strong at the Oval.
He clips Reece Topley through mid-wicket, prompting the left-armer to switch back to over the wicket.
Four balls later an overpitched delivery is superbly stroked down the ground for the second boundary of the over.
Abell is now on 143 - with Jack Leach six not out at the other end.
Bird c sub b Abbas 2 (Kent 305 v Hampshire)
End of the road for Kent as Jackson Bird tries to thrash Mohammad Abbas for four, but picks out substitute fielder James Fuller instead.
It's a decent total for the home side, who will now look to their bowlers to match the penetration of Hampshire's Keith Barker, who finishes with figures of 6-53 from 24 overs.
Warwickshire 104-4 v Essex 168
No further alarms for champions Warwickshire following the early loss of Dom Sibley and Will Rhodes.
Two runs by Matt Lamb off Mark Steketee, turned away to square leg, add a third digit to their total.
Kent 305-9 v Hampshire
Kent eke out a third batting point as Hamidullah Qadri picks up two runs through the covers off Keith Barker.
Qadri showed last week with a career-best 77 against Lancashire - that he is an improving batter, and he puts Barker away off the back foot for four to move on to 23 not out.
Northants 69-3 v Yorks 296
Northants trying to settle into their work and will be looking to Will Young, the New Zealander on debut, to make an immediate impression.
He's driven Jordan Thompson sweetly down the ground for four and pulled him for two further boundaries.
Few too many four-balls from the visitors so far after the early wicket of nightwatchman deux Matt Kelly.
Emilio Gay in on the act with three flicks backward of square on the leg side.
Gilchrist c Brown b Barker 0 (Kent 296-9 v Hampshire)
Another one for Keith Barker, another one for wicketkeeper Ben Brown.
Slightly short of a length, that delivery is far too good for Nathan Gilchrist and it's an easy fifth catch for Brown.
Last man Jackson Bird comes to the middle.
Lancs 34-1 v Glos 252
Lancashire will be out today to prove that Gloucestershire's 252 is, as widely viewed, inadequate on a good wicket.
Josh Bohannon has plenty of admirers and he's struck five boundaries already this morning - all of them off Ajeet Singh Dale.
Two lovely back-foot punches through midwicket in there.
Surrey v Somerset 302-7
Somerset secure their third batting point at the Oval with eight overs to spare as Jack leach adds two runs off Reece Topley.
His job is just to stay there in support of Tom Abell, who is 129 not out.
Stevens c Brown b Barker 23 (Kent 290-8 v Hampshire)
Image source, Getty ImagesKeith Barker completes a well-deserved five-for at Canterbury as Darren Stevens feathers a catch to Ben Brown. It's his fourth of the innings behind the stumps - three of them off left-arm paceman Barker.
Kent have eight overs to try and secure a third batting point, with just two wickets remaining.
Brett D'Oliveira is still there on 109 for Worcestershire, but they have lost Ben Cox - caught behind off Grant Stewart - and are 346-6 against Sussex.
Nottinghamshire have lost their first wicket, with Haseeb Hameed lbw to Matty Potts for 33, and are 60-1 replying to Durham's 230 all out.
No joy yet for Leicestershire, with Derbyshire 50-1 at the Incora County Ground - Shan Masood is on 27.
Toby Roland-Jones has completed a 62-ball fifty for Middlesex with a pull for four off Timm van der Gugten - they are 190-6 against Glamorgan.