D1: Kent v Essex, Middlesex v Notts, Northants v Hants, Somerset v Lancs
England opener Ben Duckett scores hundred for Notts at Lord's
Nick Gubbins and James Vince score centuries for Hampshire against Northants
Tom Abell and James Rew make unbeaten tons for Somerset against Lancashire
Only 42 overs possible between Kent and Essex because of rain
D2: Glamorgan v Durham, Sussex v Yorks, Worcs v Gloucs
Gloucestershire's Tom Price hits 93-ball hundred and takes a hat-trick at New Road
Durham reach 382-6 on the opening day against Glamorgan in Cardiff
Sussex's Tom Alsop is out five runs short of a hundred against Yorkshire
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From Jim Dale: "By anyone's standards this is a fast start from Essex, but from Essex's usual way of going about things this is supersonic. #bbccricket, external#KENvsESS, external."
Middlesex v Notts 51/0
Second bowling change from the Pavilion End as Martin Andersson replaces his captain, Roland-Jones.
Hameed drives and inside edges his second ball for a couple to take Notts past 50. Not his best shot in a largely fluent innings to date.
Orr c Bean b Thompson 20 (Sussex 48-1 v Yorks)
Image source, Rex FeaturesThe first breakthrough for Yorkshire as Ali Orr tries to pull a ball from Jordan Thompson, get an under-edge and the ball lobs up from some part of his body to Fin Bean in the slips. Tom Alsop is the new Sussex batter.
A big moment for Australia-born paceman Mickey Edwards, who is called up to bowl on debut for Yorkshire - who he has joined under a UK passport., external
Kent v Essex 70-1
Tom Westley has picked up the quick-scoring baton from Sir Alastair Cook.
He's raced to 21 from 16 balls while Nick Browne plays the anchor role at the other end.
Worcs v Glos 24-5
The wheels are coming off here.
Joe Leach has his third wicket as he hoops one into the pads in front of middle and off.
Northants v Hants 37-1
Felix Organ is squared up by Jack White but the ball squirts away to third man for four runs.
Is that a chance? Yes it is - but third slip can't hold it.
Two balls later and it's an even easier opportunity, straight to third slip, but he floors it and Organ remains on 22 not out.
You can only imagine the words currently going through White's head.
Middlesex v Notts 47-0
Roland-Jones appeals for LBW off his fifth ball but Umpire Saggers says no.
May well have struck Hameed outside the line as the opener bats outside his crease.
Rojo picks up his third maiden in a tidy spell - but no breakthroughs yet.
Somerset 38-3 v Lancashire
Lovely straight drive from Tom Kohler-Cadmore off Tom Bailey.
Kohler-Cadmore has scored just 65 runs in his four Somerset innings so far after his move from Yorkshire.
He could do with a decent knock today.
Glamorgan v Durham 40-1
The ball moves in off the seam and strikes the opener above the knee roll.
It looked a bit high but certainly adjacent and Glamorgan have their first wicket.
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From Keith: "Call Jimmy off and pop him on ice for the summer. It's unfair #bbccricket, external"
Presumably a Somerset fan, Keith?
Kent v Essex 55-1
Tom Westley sends one from Wes Agar to the boundary at deep square and that brings up the 50 for Essex.
They are rattling along at just under five an over for the loss of Sir Alastair Cook.
Middlesex v Notts 47-0
Roland-Jones is keeping Duckett quiet with seam movement into the batsman off a full length.
Duckett gets away with a single nudged into the leg side off the fifth ball.
First bowling change of the session as Ryan Higgins takes over bowling duties from Ethan Bamber, who came close to a breakthrough this morning when Duckett edged him between keeper and first slip for his first four.
Jo Gardner
Sunrisers and Oval Invincibles all-rounder
"Tremain has been a brilliant signing. I can't remember a Northamptonshire signing that has had the impact he has."
Northants v Hants 22-1
Felix Organ is fortunate as he tries to drive the final ball of Chris Tremain's opening over and fails to make contact.
His foot wasn't to the pitch but the Aussie has to settle for a maiden, not a wicket maiden.
Bancroft c Bell b Bailey 7 (Somerset 24-3 v Lancashire)
Somerset bang in trouble here!
Tom Bailey rarely misses out with the new ball and he gets in on the act with a terrific ball to Cameron Bancroft.
It does enough to take the Aussie's edge from a good length delivery and Lancashire are in business.
Bancroft falls for a difficult seven.
Middlesex v Notts 46-1
Bamber is into his sixth over now and bowling round the wicket.
Duckett tries to paddle it to fine leg and runs two byes.
A pull to leg for two off the second ball and a neat deflection for three behind gully.
Hameed gets a thick edge on the fifth ball, but still drives it through the covers for four.
Kent v Essex 47-1
Alex Hoad
BBC Sport at Canterbury
Image source, Rex FeaturesIn July 2013 Ashton Agar had plain old Alastair Cook, as he was known then, caught by Michael Clarke for 50 at Trent Bridge to register his first Test wicket.
Fast-forward nearly 10 years and his younger brother Wes has his first scalp in England, and it just had to be Sir Alastair Cook.
The word on the cobbled streets of Canterbury is that wicket might just have earned the younger sibling a few dollars from the older too.
What a way to introduce yourself to your new fans in the Garden of England.
A Cook c Billings b Agar 39 (Kent v Essex 43-1)
Short, with a bit of width outside off-stump from an Australian to Sir Alastair Cook. It's like 2010/11 all over again as Cook sends it to the fence.
Three fours in a row!
But Wes Agar gets his revenge as Cook gets an inside edge and is caught behind.
His exciting innings of 39 from just 30 balls with eight fours is over.
Shame for Essex. Relief for Kent.
Northants v Hants 22-1
That is what they call a good leave.
Nick Gubbins offers no stroke to an angled ball by Jack White and it must have been very adjacent to off stump.
Chris Tremain relieves Ben Sanderson at the other end.
Lammonby c Jennings b Anderson 15 (Somerset 24-2 v Lancashire)
Image source, Rex FeaturesThere is absolutely no substitute for class!
Jimmy Anderson puts one in the perfect area bowling over the wicket to a left-hander and Tom Lammonby is drawn forward into the shot.
The ball takes the edge and it's a regulation catch at second slip.