Gloucestershire have won the toss and will bat first in their delayed game against Sussex at Bristol.

Home captain Michael Klinger is averaging 228.5 in the competition so far after hitting three centuries, but he still trails Chris Gayle, who left Somerset with an average of 328 from his three innings, in the rankings.

Gloucestershire will leapfrog Sussex in the South Group with a win, but the visitors, who include Australia's George Bailey, know victory would give them some breathing space in the chase for the quarter finals.

Gloucestershire: Klinger, Marshall, Handscomb, Cockbain, Howell, Jones (wkt), Taylor, Fuller, Smith, Miles, Noema-Barnett.

Sussex: Nash, Wright, Bailey, Cachopa (wkt), Machan, Yardy, Finch, Beer, Robinson, Liddle, Mills.

Middlesex have taken their foot off the gas after hitting the first few overs all over the park. Just five runs off the seventh over of the innings and Eoin Morgan, a man in such superb form for England, has a strike rate of just 30.00 so far. And that's not a typo...

From OptaJim:, external "38 - Most @NatWestT20Blast sixes since start of 2014: @lukewright204 (38), @Stevo208 (31), @henrygayle (29), @ravibopara (28). Lofty."

Image source, Getty Images

A massive top edge from David Willey sees his big-hitting come to an end. Having struck two further successive straight sixes, the England all-rounder is caught by Jack Shantry off Saeed Ajmal's bowling for a rapid 31 off 12 balls. It was fun while it lasted.

Image source, Getty Images

South Group leaders Kent do not have a T20 Blast game this evening, but there is good news for batsman Sam Northeast, who has agreed what the club has described as a "long-term contract extension".

Northeast has hit 520 T20 runs so far this season, with a stratospheric strike-rate of 162, to go with 672 runs in the County Championship.

Read the full story here

Yorkshire strike an early blow when Matt Fisher has Foxes captain Mark Cosgrove caught by Jack Leaning in the covers for four in the second over.

Kevin O'Brien sets his stall out immediately, hitting his first ball for four, but is then rather luckier to find the boundary as he thick edges Fisher through the slips for another four.

But the Vikings bowlers are using the green pitch to good effect, producing 10 dot balls from their last 13 as Ned Eckersley and O' Brien guide the hosts to 28-1 after five.

It's the man many of the crowd in Uxbridge have been waiting to see: Eoin Morgan makes his way to the crease for Middlesex on a track which looks like a batsman's dream so far - albeit one which Tim Groenewald has managed to take two much-needed wickets on for Somerset.

For those of you trying, without success, to listen to live radio commentary from Uxbridge, we're currently experience a technical issue - but hopefully we'll have it fixed as soon as possible.

BBC Radio Northampton's Alex Winter: "David Willey is not looking good and has clearly got a problem with his left ankle. He looks in some pain."

Willey has just hit Jack Shantry for two successive sixes but then appeared to collide with the bowler as he ran.

A blistering start from Northants opener Richard Levi comes to an end. Having smashed 19 from 10 balls he is out in the third over, caught by Moeen Ali in the deep off the bowling off Jack Shantry.

From Warwickshire CCC:, external "Closures of M6 has severely disrupted player travel plans; several players still travelling & will update when we can"

Flat Track Bully: Got Alex Hales as my #FantasyCricket captain this week. Notts Outlaws double-header should spell big runs. #bbccricket

Nottinghamshire face Derbyshire from 19:00 BST.

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Who'd be a bowler? It's a question we're getting used to hearing and let's ask it again... Nick Compton and Paul Stirling go on the attack from the off, hitting the first over for 12 and the second for 22 - with four boundaries and two sixes flying off the bat so far.

As for our other early start, it sounds like play will get under way half an hour late in Bristol, with the covers off and the toss expected to take place in 10 minutes or so at 17:40 BST. All set fair for an 18:00 BST start...

It looks like we're now under way in three of our four 17:30 BST matches, so let the mayhem commence!

Image source, Getty Images

So, there's some big guns in action this evening, with McCullum, Morgan, Hales et al donning county colours after playing in the recent one-day international series.

But who you think is going to make the biggest mark on today's programme?

Let us know using #bbccricket on Twitter.

From OptaJim:, external "254 - The highest score in English domestic T20s was recorded at Uxbridge (254/3, by Gloucestershire in 2011). Feast. @SomersetCCC"

Fresh from leading England to victory over New Zealand in the Twenty20 international on Tuesday, Eoin Morgan is named in the Middlesex side to face Somerset, while spinner Ravi Patel comes back after a broken thumb.

Somerset bring New Zealand star Luke Ronchi in for his debut, while Tim Groenwald comes into the bowling attack to replace Sohail Tanveer.

Middlesex: Stirling, Compton, Simpson, Morgan, Franklin, Balbirnie, Higgins, Rayner, Abbott, Harris, Patel

Somerset: Allenby, Myburgh, Trego, Hildreth, Cooper, Ronchi, Groenewald, Thomas, Waller, J Overton, Rehman

BBC Sussex's Adrian Harms on Twitter: Toss delayed at Bristol commentary from 5.30 on line @BBCSussexSport if the rain stops @SussexCCC #bbccricket

Image source, @AdrianHarms

Group leaders Worcestershire are unchanged from the side that beat Lancashire Lightning and Derbyshire Falcons in their last two T20 Blast fixtures so England's Moeen Ali once again opens the batting.

Northants also look strong up top, with opening pair David Willey and Richard Levi the men entrusted with setting up a win to propel them in to the top four.

Worcestershire: Mitchell (capt), M Ali, Munro, D'Oliveira, Kohler-Cadmore, Whiteley, Cox, Barnard, Leach, Saeed Ajmal, Shantry.

Northants: Levi, Willey, Cobb, Wakely (capt), Duckett, Crook, Rossington, Keogh, Kleinveldt, White, Azharullah

Worcestershire have won the toss and opt to put Northants into bat - live commentary via the Live Coverage tab.

Charles Dagnall
BBC Test Match Special

Image source, Charles Dagnall

"View currently from the @bbctms box at Old Trafford... For #TMSt20 Being told it will clear soon..."