Hampshire's fourth-wicket stand of 224 finally comes to an end.
Tom Alsop falls for a brilliant 119 to Alex Evans as he tries to flick him off his hip but gets a leading edge which is caught in the off side.
James Vince is still there on 144.
Post update
Middlesex 250-5 v Somerset
Floodlights are shining brightly at grounds now, including Lord's where Middlesex have just reached 250 to earn a second batting bonus point.
Sam Robson has 160 of those.
Nice to see the revamped Compton and Edrich stands are taking shape as well...
Getty ImagesCopyright: Getty Images
Bad light stops play at Chelmsford
Essex 206-3 v Worcestershire
Players off at the County Ground.
Even with their new-fangled all-singing, all-dancing floodlights on, umpires David Millns and Neil Mallender have decided the artificial light is taking over the natural light.
Still just under 16 overs scheduled in the day's play, but that may well be it as Tom Westley heads to the pavilion unbeaten on 84 and Paul Walter on 26 in a stand currently worth 76 for the fourth wicket.
Get Involved
Tweet us using #bbccricket
David Talbot: Just looked out my back window and I can confirm it is gloomy but the new lights at Essex are impressive!
I'm in the West Midlands and I might need to get my torch out in a sec.
Douthwaite goes big!
Yorkshire v Glamorgan 211-7
Some big-hitting coming out now from Glamorgan all-rounder Dan Douthwaite.
He smashes a four and six off consecutive balls from Duanne Olivier shortly after Glamorgan pass 200.
Douthwaite on 43 now off 60 balls. Timm van der Gugten unbeaten on 36 at the other end.
for Robson
Middlesex 237-5 v Somerset
Sam Robson continues to pile on the runs on the opening day.
The Middlesex opener brings up his 150. What a knock this has been when the other batsmen have found runs hard to come by.
In fact, the next top score is Stevie Eskinazi's 22.
Getty ImagesCopyright: Getty Images
Vince continues to dominate
Group 2 update
Elsewhere in Middlesex's group, Hampshire continue to put Leicestershire to the sword.
James Vince has motored onto 135 off 124 deliveries to take his side to 331-3. Tom Alsop also has an unbeaten century to his name.
Gloucestershire and Surrey are back on after a rain delay and Surrey have just lost their ninth wicket - Jamie Overton chopping onto his stumps. 207-9.
Glamorgan resistance continues
Yorkshire v Glamorgan 193-7
No breakthroughs so far after tea for Yorkshire's bowlers.
Dan Douthwaite (33 not out) and Timm van der Gugten (28 not out) making what could be some very valuable lower-order runs at Headingley for the visitors.
They've added 61 now for the eighth wicket.
First wicket for Gay
Group 3 update
Getty ImagesCopyright: Getty Images
An inspired bowling change by Northants has given them the breakthrough against Kent.
Emilio Gay has claimed his maiden first-class wicket with just his third ball today as Jack Leaning nicks him behind for 79.
Kent are 230-5.
In the other match in Yorkshire's group, Sussex are staging some recovery from 127-6. They're now 232-6 with Tom Haines unbeaten on 144. Ollie Robinson has 48 in a stand worth 105.
Back on at Edgbaston
Group 1 update
A brief interupption there for bad light at Edgbaston.
Warwickshire's bowlers back out there trying to wrap up Derbyshire's innings at 178-9.
At Trent Bridge meanwhile, Nottinghamshire have picked up two quick wickets in Durham's innings.
Ned Eckersley and Stuart Poynter fall in consecutive overs as they slump to 196-7.
Rex FeaturesCopyright: Rex Features
Lights on at Chelmsford
Essex 190-3 v Worcestershire
PA MediaCopyright: PA Media
Exciting times this - they've switched on the new and improved floodlights at the County Ground with the skies also starting to darken at Chelmsford.
Tom Westley (81 not out) and Paul Walter (13 not out) meanwhile have added 60 for this fourth wicket to move towards a first batting bonus point.
Live Reporting
Adam Williams and Gary Smee
All times stated are UK
Close of play at Bristol
Gloucestershire v Surrey 220-9
Rain has curtailed the opening day between Gloucestershire and Surrey.
Led by Josh Shaw (4-48), the hosts will surely be pleased with their efforts in reducing Surrey to 220-9.
Run-fest continues for Glamorgan
Yorkshire v Glamorgan 244-7
It's runs, runs and more runs at the moment for Glamorgan at Headingley.
Yorkshire's bowlers are fuming as Dan Douthwaite and Timm van der Gugten fly past a 100 partnership for this eigth wicket.
Van der Gugten has also reached his 50 off 97 balls with seven fours and a six.
A fantastic effort from this pair.
WICKET
Robson c Abell b Gregory 165 (Middlesex 263-7 v Somerset)
There's the one Somerset wanted!
Sam Robson's fantastic knock is ended by Lewis Gregory as he edges him to Tom Abell at slip.
The new ball is reaping some late rewards for the visitors at Lord's.
Derbyshire dismissed for 189
Warwickshire v Derbyshire 189
Derbyshire bowled out at Edgbaston for 189.
Danny Briggs claims the final wicket of Sam Conners for nine.
Liam Howell finishes with 5-32 off his 18 overs.
Light permitting, the Bears will have about 10 overs to bat before stumps.
WICKET
Simpson c Davies b Gregory 11 (Middlesex 254-6 v Somerset)
Somerset keep on striking just when they need it!
John Simpson snicks Lewis Gregory behind to leave Middlesex six down.
Toby Roland-Jones joins Sam Robson (160 not out) in the middle.
for Haines
Lancashire v Sussex 253-6
Some big scores for the batsmen today.
Sussex's Tom Haines becomes the third man to go past 150.
Fine innings from the 22-year-old to help Sussex recover from 14-3 and 127-6.
for Vince
Leics v Hants 367-4
James Vince's brilliant knock for Hampshire rolls on.
He goes to 152 off 140 balls with a 25th boundary.
Sensational innings from the skipper.
for Dan Douthwaite
Yorkshire v Glamorgan 226-7
Half-century up for Dan Douthwaite as Glamorgan's lower-order resistance rumbles on.
He gets there with a nudged single off Joe Root to bring up his 50 from 75 balls, including eight fours and a six.
Timm van der Gugten meanwhile isn't far behind joining him with 44 off 82 balls as he hammers Root for a straight six at the end of the same over.
Post update
Lancashire v Sussex 246-6
Another decent stand in Group 3 between Tom Haines (147 not out) and Ollie Robinson (59 not out)...
WICKET
Alsop c Mike b Evans 119 (Leics v Hants 351-4)
Hampshire's fourth-wicket stand of 224 finally comes to an end.
Tom Alsop falls for a brilliant 119 to Alex Evans as he tries to flick him off his hip but gets a leading edge which is caught in the off side.
James Vince is still there on 144.
Post update
Middlesex 250-5 v Somerset
Floodlights are shining brightly at grounds now, including Lord's where Middlesex have just reached 250 to earn a second batting bonus point.
Sam Robson has 160 of those.
Nice to see the revamped Compton and Edrich stands are taking shape as well...
Bad light stops play at Chelmsford
Essex 206-3 v Worcestershire
Players off at the County Ground.
Even with their new-fangled all-singing, all-dancing floodlights on, umpires David Millns and Neil Mallender have decided the artificial light is taking over the natural light.
Still just under 16 overs scheduled in the day's play, but that may well be it as Tom Westley heads to the pavilion unbeaten on 84 and Paul Walter on 26 in a stand currently worth 76 for the fourth wicket.
Get Involved
Tweet us using #bbccricket
David Talbot: Just looked out my back window and I can confirm it is gloomy but the new lights at Essex are impressive!
I'm in the West Midlands and I might need to get my torch out in a sec.
Douthwaite goes big!
Yorkshire v Glamorgan 211-7
Some big-hitting coming out now from Glamorgan all-rounder Dan Douthwaite.
He smashes a four and six off consecutive balls from Duanne Olivier shortly after Glamorgan pass 200.
Douthwaite on 43 now off 60 balls. Timm van der Gugten unbeaten on 36 at the other end.
for Robson
Middlesex 237-5 v Somerset
Sam Robson continues to pile on the runs on the opening day.
The Middlesex opener brings up his 150. What a knock this has been when the other batsmen have found runs hard to come by.
In fact, the next top score is Stevie Eskinazi's 22.
Vince continues to dominate
Group 2 update
Elsewhere in Middlesex's group, Hampshire continue to put Leicestershire to the sword.
James Vince has motored onto 135 off 124 deliveries to take his side to 331-3. Tom Alsop also has an unbeaten century to his name.
Gloucestershire and Surrey are back on after a rain delay and Surrey have just lost their ninth wicket - Jamie Overton chopping onto his stumps. 207-9.
Glamorgan resistance continues
Yorkshire v Glamorgan 193-7
No breakthroughs so far after tea for Yorkshire's bowlers.
Dan Douthwaite (33 not out) and Timm van der Gugten (28 not out) making what could be some very valuable lower-order runs at Headingley for the visitors.
They've added 61 now for the eighth wicket.
First wicket for Gay
Group 3 update
An inspired bowling change by Northants has given them the breakthrough against Kent.
Emilio Gay has claimed his maiden first-class wicket with just his third ball today as Jack Leaning nicks him behind for 79.
Kent are 230-5.
In the other match in Yorkshire's group, Sussex are staging some recovery from 127-6. They're now 232-6 with Tom Haines unbeaten on 144. Ollie Robinson has 48 in a stand worth 105.
Back on at Edgbaston
Group 1 update
A brief interupption there for bad light at Edgbaston.
Warwickshire's bowlers back out there trying to wrap up Derbyshire's innings at 178-9.
At Trent Bridge meanwhile, Nottinghamshire have picked up two quick wickets in Durham's innings.
Ned Eckersley and Stuart Poynter fall in consecutive overs as they slump to 196-7.
Lights on at Chelmsford
Essex 190-3 v Worcestershire
Exciting times this - they've switched on the new and improved floodlights at the County Ground with the skies also starting to darken at Chelmsford.
Tom Westley (81 not out) and Paul Walter (13 not out) meanwhile have added 60 for this fourth wicket to move towards a first batting bonus point.