Ollie Robinson has bowled a good opening seven-over spell, taking 1-18 but he's asked to take a breather as Jayden Seales returns.

At the other end, Fynn Hudson-Prentice gets his first wicket of the day, bowling Brooke Guest for 22 to reduce the hosts to 50-2.

Wayne Madsen comes to the crease.

At Headingley, Billy Root brings up the Glamorgan fifty as he hits a Matthew Fisher effort ball to the boundary in front of the Eastern Stand.

He then profits from some loose stuff off Fisher to take another four. He moves to 25 with Glamorgan on 55-1.

A bit more luck for Essex on a very tough morning, as Lewis Gregory spears a ball leg side, resulting in four leg byes to take the visitors past 50 in the 15th over.

An appeal for a catch down the leg side by keeper James Rew off the bowling of Migael Pretorius is turned down.

A tiny hint of blue sky emerges overhead and Essex will hope for calmer batting conditions to come.

Zak Crawley moves on to 20, gently running a ball from Balderson through gully.

Two runs for Compton, pushed through deep backward square leg.

Kent have battled hard, doing well in swinging and seaming conditions to keep all their wickets intact.

Nick Gledhill
BBC Essex

For Somerset this is a game plan coming off as they bid to close the gap on the leaders.

It’s a greenish pitch, Somerset are fielding an all seam attack and there’s bounce and movement under cloud cover.

Craig Overton and Josh Davey have largely put the ball in the right place and let the wicket do the rest.

Essex left out Feroze Khushi following a fitness test after he had suffered back pain during the Durham game.

With Tom Westley returning following the birth of his daughter it prevented an awkward selection decision over which batsman to leave out had they wanted to play a fourth seamer on this pitch.

We may be in the thick of the Championship, but the T20 Blast is fast closing in on the horizon.

Northamptonshire have strengthened their ranks ahead of the new campaign with the signing of South African top-order batter Matthew Breetzke.

It looks a good 'un. The 25-year-old was the leading scorer in the recent CSA T20 Challenge in his home country.

The rain has taken the honours in the morning session at Lord's

The covers have remained on at the home of cricket and there will be no play this morning.

The players will help themselves to an early lunch at 12.30pm and hope for better this afternoon. The forecast suggests the rain will stop between 2pm and 3pm.

Migael Pretorius replaces Davey in the Somerset attack and starts with just a single off his first over.

Lewis Gregory has Tom Westley playing around his front pad as he gets the ball to bounce and nip away off the seam.

Maiden over.

Tom Bailey is round the wicket to the left-handed Ben Compton, who leaves the ball outside off.

A hint of away swing for Bailey as Compton pushes forward, just inside the line.

No breakthrough yet.

Image source, Getty Images

Rare moments of respite for Essex this morning as Matt Critchely gets four runs off a thick edge just wide of third slip.

Somerset captain Lewis Gregory replaces Craig Overton at the other end - and there's a brief pause in play as more sawdust is brought on for the bowler's footmarks.

Tom Westley gets a single to the on side off the third ball.

Gregory has Critchley in trouble as he's rooted to the crease, playing and missing with a horizontal bat outside off.

The last ball is driven through mid off, beating a late dive from Tom Banton for four runs.

Derbyshire have made a decent start after being put in to bat by Sussex.

After the early loss of skipper David Lloyd to Ollie Robinson, Luis Reece (10*) and Brooke Guest (18*) have taken Derbyshire to 46 without further damage off 11 overs.

A decent lick.

It's more a case of toil on a used pitch at Leeds where Billy Root (12*) and Sam Northeast (6*) have taken Glamorgan to 27-1 after 13 overs.

Ben Coad has the sole wicket and looks the man most likely to winkle out a few more wickets. And the lights have just come on at Headingley.

George Balderson is in the attack now, replacing Will Williams and has Ben Compton playing and missing outside off stump.

Tom Bailey then goes close to a breakthrough as Zak Crawley is beaten by a ball that just passes over his stumps.

Crawley gets away with a couple of runs squeezed away to backward point.

Annie Chave
BBC Somerset

Somerset very much showing why they've chose five seamers.

They are doing very well at the moment.

It's good to see that there is a bit of movement in the pitch.

Both bowlers are bowling incredibly well in these good conditions for them.

Overton is into his fifth over and continues to cause Essex problems.

He gets one ball to leave Tom Westley on the line of off stump, squaring up the Essex captain.

But the fourth ball is full and whipped through mid on for four runs.

Tom Bailey bowls just outside off and Zak Crawley plays defensively to backward point.

The fourth ball is pushed with soft hands into the off side for one.

One more run to Ben Compton, who pushes the ball down the ground.

Nick Gledhill
BBC Essex

Somerset will sense an opening. Another wicket here quickly and there could be a bit of a problem for Essex.

These are good bowling conditions. It's cloudy, there's a little bit of movement around and a hint of green.

It was an important toss for Somerset to have won and they've got the bowlers to exploit it.

Good footwork from Jordan Cox, who is well forward to Josh Davey, pushing the ball through wide mid on for a single.

Westley plays and misses but sees out the over.

Ben Coad makes an early breakthrough for Yorkshire.

After seeing an edge off Billy Root put down by Root senior earlier, Coad pins opener Eddy Byrom in front for nine.

A bit of width from Will Williams and Ben Compton gets off the mark with a deft cut to point for four.

He ends the over playing the last ball defensively into the gully.

Steady start for Kent.