D1 leaders Surrey enforce follow-on after bowling out Warwickshire for 161
Hampshire's Liam Dawson out for 115 against Somerset at the Ageas Bowl
Lancashire's Josh Bohannon passes 1,000 Championship runs for the season
Middlesex's Josh de Caires takes 7-105 against Essex at Chelmsford
Durham's Alex Lees hits fifth Championship hundred of the season against Sussex
Leicestershire bowled out for 204, but lead Gloucestershire by 45 on first innings
Hants 308 v Somerset 0-0
Keith Barker has the new ball for Hampshire, and Tom Lammonby plays out a maiden to start proceedings.
Andy Umeed is carded at four for Somerset, despite his remarkable run of form opening the batting in white-ball competition.
Yorkshire 297 v Derbyshire 109-3
The first maximum of the Derbyshire innings as Wayne Madsen launches Ben Coad over long-on for six.
He obviously couldn't keep his Hundred mindset under wraps any longer.
Durham 66-1 v Sussex 266
Another superb shot by Alex Lees, stroked through extra cover for four off Fynn Hudson-Prentice and he is into the 40s at the Riverside.
The opener is rapidly closing in on 1200 red-ball runs for the season.
Yorkshire 297 v Derbyshire 103-3
The end of opener Mitch Wagstaff as he goes to pull Matt Fisher but it comes up high on the bat and it loops it square leg.
This game is evenly poised in sunny Scarborough.
Northants 232 v Lancashire 101-4
Dane Vilas gets off the mark with a firm drive through the offside for four to take his county to three figures.
Vilas is retiring from Championship cricket at the end of this match but he has been short of runs all summer.
Maybe his final few weeks will see an upturn in form.
Surrey 396 v Warwicks
It's been Ed Barnard's morning at The Oval.
Three wickets to complete his first five-for for Warwickshire and he ends Surrey's first innings by taking the catch at deep mid-wicket to finally bring Ben Foakes' 210-ball innings to an end.
Foakes was going for a 20th boundary to secure a fourth batting point, but got underneath an attempted slog sweep and they are four runs short as he walks off.
Worcs 284 v Glamorgan 40-3
We've had three successive maidens at New Road, as Glamorgan dig in following the loss of three early wickets.
Logan van Beek has come into the attack and found his rhythm immediately, not giving Sam Northeast and Colin Ingram anything to work with.
Van Beek should have had a wicket too, but Northeast was dropped at midwicket.
Yorks 297 v Derbys 102-2
This is Mitch Wagstaff second first-class match - and first since May - but he has a 99-ball 50, which he brings up with a boundary, steered to third man, off George Hill.
Surrey 396-9 v Warwicks
A short ball by Oliver Hannon-Dalby and Dan Worrall gloves it to the keeper. Or does he?
Worrall has to go but clearly believes that came off his arm.
Wouldn't like to be OHD if Worrall has the ball when it is his turn to bat.
Northants 232 v Lancashire 97-4
The wicket Northants really wanted!
Phil Salt was looking to score quickly and he comes down the wicket to Tom Taylor but his attempted pull only goes high up in the air and running back from slip, Gay takes the catch.
Salt goes for 22 and the deficit is still 135.
Hants 308 v Somerset
Kyle Abbott had played some eye-catching shots for his 14, but this one is slightly uppish, and he finds the safe hands of Tom Abell in the covers.
Hampshire are all out for 308, and Abbott's focus will switch to bowling.
Gloucestershire have their first wicket of the day at Grace Road where Colin Ackermann was brilliantly caught at second slip by Ollie Price off Zaman Akhter for 33.
He put on 79 with Rishi Patel and Leicestershire are 150-3, just nine runs away from parity.
A good stand is developing at Scarborough, with Derbyshire now 94-2 in the 31st over against Yorkshire. Mitch Wagstaff (47) and Wayne Madsen (33) have added 48 so far.
Essex 62-0 v Middlesex
A lovely first hour of batting for Nick Browne and Sir Alastair Cook.
Browne has 36 and the batting knight has 26 and Essex have been given a very nice platform for the rest of the day.
Josh de Caires has already whizzed through five overs of off-spin - expect him to have a long spell today.
Surrey 394-8 v Warwicks
Warwickshire give Ed Barnard a breather and spinner Danny Briggs takes up the attack.
Dan Worrall flicks him away off his pads for four and follows it with another boundary to progress to 26 not out.
Another half an hour of this and it's be very bad news for Warwickshire indeed.
Surrey 383-8 v Warwicks
You won't see that in any non-Bazball coaching manual.
Dan Worrall makes room and smears Chris Rushworth away cross-batted for four to extra cover.
His front foot could hardly have been further from the pitch of the ball.
But it's the result that counts, right?
Northants 232 v Lancs 90-3
Scott Read
BBC Radio Lancashire
Phil Salt signed off for the Hundred with a 74-ball century against Northamptonshire in the County Championship at the end of July.
It was one of the most brutal displays of red-ball batting you're likely to see and his first game back is against the same opponents.
However, the approach has been a little different so far. The pitch is offering just enough to keep the bowlers interested but Lancashire will be aiming to bat once.
Northants have been frail with the bat for most of the season and quickly crumbled on the opening day. If the Red Rose are still batting after tea a must-win game for the home side will be fading away.
Durham 43-1 v Sussex 266
Alex Lees doesn't appear to believe his England Test career is over - he's clearly been watching the way the national team play nowadays.
The left-hander picks up a respectable delivery from Ari Karvelas and deposits it over mid-wicket for six.
Wonder if Ben Stokes is at Chester-le-Street today?
Northants 232 v Lancashire 86-3
Some real intent from Phil Salt as he crunches three fours in five balls off Tom Taylor.
That takes him to 18 off 20 balls.
In the last Championship game in July, Salt smashed 105 off just 77 balls against these same opponents at Old Trafford.
Surrey 375-8 v Warwicks
What Warwickshire can't afford now, having started the day so well, is a flurry of runs from the Surrey tail.
Ed Barnard drops fractionally short and is pulled for four by Ben Foakes, and Dan Worrall helps himself to a boundary to end the over.
Essex 51-0 v Middlesex
A lovely off-drive gets Sir Alastair Cook four runs and it brings up the half-century partnership between him and Nick Browne.
An excellent start for Essex.