Durham need skipper Paul Collingwood to be at his most limpet-like today if they are to somehow avoid defeat at Headingley. He now has Graham Clark with him in the middle, as they try to keep Ryan Sidebottom and Jack Brooks at bay.

Meanwhile, here's a nice photo of some limpets for you.

Hampshire could certainly do with a Ryan Sidebottom-like performance from one of their bowlers today, but they have had no joy so far at The Oval. Dominic Sibley and Rory Burns have added 19 runs so far, and Surrey now need another 209 to make Hampshire bat again. 

Harry Gurney and Jake Ball open up for Notts at Trent Bridge, but Middlesex come through the first three overs unscathed - and need another 178 to win. This is a very big day for both teams. Which one has the stronger nerve? 

Durham's Graham Onions made the first half-century of his county career as a nightwatchman in last week's game against Notts. They certainly need something similar from him today.

Ryan Sidebottom's opening delivery of the day runs away for four leg-byes and Onions adds a boundary later in the over. Only 374 now needed by Durham for victory!

Is rain going to affect the denouement of our games at Trent Bridge, The Oval and Headingley?

You can watch Jay Wynne's UK video forecast by clicking here or for more localised information, go to the BBC Weather site and enter Nottingham, London or Leeds in the 'Fine A Forecast' box. 

  You can hear ball-by-ball coverage from our BBC radio teams by clicking the 'live coverage' tab at the top of this page and selecting the match of your choice - while keeping up to date with what is happening in the other two matches by reading this page.  

Image source, Surrey CCC

Should Yorkshire - the title winners in 2014 and 2015 - defeat Durham and Middlesex lose at Trent Bridge, then the White Rose county will have a 15-point lead in the Division One table.

Should both teams win, Middlesex will lead Yorkshire by a single point, with Somerset 22 points back in third place

In the latter scenario, a Middlesex win would also send Notts down to Division Two for 2017.

Surrey's lingering hopes of the title appear to be fading away at The Oval where Hampshire appear to be the only side with a chance of victory.

If Hampshire win and Durham lose, then the two sides will become locked in a five-way battle to avoid relegation, also involving Lancashire and Warwickshire - or a four-way battle if Notts lose against Middlesex.

Just contemplating all of that has made my head ache - I'll worry about what happens if any of today's games is drawn later on....  

PS If any of my calculations is awry, please tweet us at #bbccricket and let me know 

Nottinghamshire 241 & 240 v Middlesex 247 & 48-3

Middlesex need another 187 for victory

Surrey 329 & 23-0 v Hampshire 582-9 dec

Surrey need another 230 to avoid an innings defeat

Yorkshire 460 & 225-2 dec v Durham 265 & 39-3

Durham need another 382 for victory

Yesterday's result at Taunton certainly put the Somerset cat among the Yorkshire and Middlesex pigeons in the County Championship title race.

Only three of the seven matches that began on Tuesday have reached the fourth and final day, but each one will have major consequences for the teams involved.

As Billy Ocean once said 'when the going gets tough, the tough get going' - and now is the time to find that mind-set with just two rounds of games to go after this one.

Welcome to our coverage of what should be an enthralling day of action. Play starts at 10:30 BST.

Image source, Getty