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Division One leaders Hampshire and third-placed Lancashire not in action
Second-placed Surrey at Northants and will reclaim first place if they avoid defeat
Warwickshire host Somerset in key game at bottom of Division One table
Second-placed Glamorgan visit fourth-placed Middlesex in Division Two, with both sides in promotion picture
Northants 166-3 v Surrey
A lovely little clip to the fine leg fence for four more to Emilio Gay off Tom Curran.
The perfect way to end the session as Gay heads for a quick cup of tea unbeaten on 107.
Image source, Getty Images
Somerset 76-6 v Warwickshire
Henry Brookes strikes in only his second over and Lewis Goldworthy is gone.
Lewis Gregory is still there, now joined by Kasey Aldridge. But the visitors look so uncomfortable on this pitch they may well to get past 100.
Sussex 220 all out v Worcestershire
Sussex spinner Jack Carson is last man out, run out for 56 - the fourth half-century of his career.
Now it's time for Worcerstershire to bat.
Having seen the Sussex tailenders going for their shots, what sort of effect will that have on Pears opener Ed Pollock?
Either way, he'll have to wait until after tea.
Sussex 219-9 v Worcestershire
Sussex have rallied well from 23-5 to claim a batting point - and Jack Carson is still going strong.on 56
Northants 154-3 v Surrey.
Emilio Gay has been in good nick from the off this morning and he brings up a deserved century with a flick off his hips.
This has been a terrific knock, reaching three figures off 118 balls with 13 fours at a strike rate of just under 85.
It's his third Championship century, but the first one on his home ground.
Somerset 60-5 v Warwickshire
It has not been without incident or alarm, on a pitch that seems to be doing a bit, but the two Lewises - Gregory and Goldsworthy - have so far lasted six overs and added 14 runs for Somerset.
Brief respite after the shock of losing those three wickets on 46 inside the space of six deliveries.
Yorkshire 134 all out v Essex
There is going to be an extended tea break at Headingley, where it has started raining and the covers have come on.
Northants 146-3 v Surrey
Emilio Gay helps himself to three more and he has now put on 52 for the fourth wicket with Rob Keogh at a good rate.
Gay now has 94.
Glamorgan 214 v Middlesex
Ajaz Patel's 27 balls of plunder come to an end as he is caught behind for 36, last man Michael Hogan stays for just eight deliveries - and Glamorgan are all out.
Both wickets to Ryan Higgins, who finishes with 4-59, to back up the key earlier efforts of Tim Murtagh (3-58) and Toby Roland-Jones (2-50).
Now comes Hogan's own turn to have a bowl, although not until after tea, which has now been taken.
Sussex 198-8 v Worcestershire
Half-century for Sussex's Jack Carson - but it's 50 and out for James Coles, who departs, having earned Ben Gibbon a second wicket.
Northants 140-3 v Surrey
Almost the downfall of Emilio Gay as he takes on a short ball from Gus Atkinson.
He reaches for it as he sends it high towards the midwicket boundary, but it falls just short of fielder Ben Geddes in the deep.
Gay takes two to move up to 90.
Somerset 46-5 v Warwickshire
And another.
Three wickets in six balls.
Mohammed Siraj on a hat-trick . . .
3-18 on his debut for the India international.
But winning Hundred skipper Lewis Gregory sees off the hat-trick ball.
Yorkshire 134 all out v Essex
The last pair had survived for more than seven overs, but the innings is now over.
Jack Shutt is hit on the pads by Jamie Porter and he is given out LBW.
An excellent performance by Essex with the ball. A real team effort with three wickets apiece for Sam Cook and Shane Snater and two for Ben Allison and Porter.
Although Yorkshire will hope to make similar inroads when they take to the field.
Somerset 46-4 v Warwickshire
And another one . . .
Mohammed Siraj gets in on the act again too as he George Bartlett is well taken by wicketkeeper Michael Burgess, running back to take a very good catch.
Youngster James Rew is the next man in.
Somerset 46-3 v Warwickshire
India spinner Jayant Yadav strikes for Warwickshire in his first over, witrh only his third ball.
Tom Lammonby gave him the charge and that proved a routine stumping for keeper Michael Burgess.
Sussex 171-7 v Worcestershire
Another side in the middle of a rescue mission are Sussex, who have recovered from 23-5 to 171-7.
Sussex teenager James Coles, playing only his seventh first-class match, has gone to his second fifty.
He has, more importantly, so far put on 65 for the eighth wicket with Irish spinner Jack Carson.
Glamorgan 204-8 v Middlesex
At 48-4 - and again at 165-8 - a batting bonus point for Glamorgan did not seem that likely. But Ajaz Patel has come in to swing the bat and it has paid off, with seven fours in a quickfire 36 off 23 balls.
"Something to play with now" for the visitors, points out BBC Wales' Eddie Bevan.
Leicestershire 97-2 v Durham
Better news from Leicester.
There is now reportedly an inspection scheduled for umpires Tom Lungley and Chris Watts at 3.00.
Northants 124-3 v Surrey
Emilio Gay underlines that importance with the shot of the day.
He dissects two fielders with a lovely cover drive off Kemar Roach. That is his 12th of the innings as he moves into the 80s.
Northants 114-3 v Surrey
The scorecard reads much better now for Surrey, with captain Rory Burns having asked Northants to bat this morning.
They would love to remove Emilio Gay, though. The opener now has 77 out of a total of 114.