Surrey's batting capitulated for the second time as Middlesex sealed an innings win before tea on day three.
Steve Finn claimed 4-19 as Middlesex crushed Derbyshire by an innings and 35 runs with a day to spare at Lord's.
Kent completed a 10-wicket victory over Middlesex to open a 36-point lead at the top of Division Two.
Neil Dexter is set to leave Kent after turning down a new deal at the club because he wants to play more first-team cricket.
Essex have taken Neil Dexter on a month's loan from Kent.
Tri-Series in Australia 2015
Australia win by 112 runs
Australia and New Zealand will co-host the 2015 Cricket World Cup from February - here's a taster of what's in store.
England can take great heart from reaching Sunday's Tri-Series final with a tough win over India, says David Lloyd.
David Lloyd raises a glass to the 'Tubby' Taylor wine tour, the BBL and England's showdown with India.
England's World Cup opponents will not relish the return of fit-again James Anderson, says Nick Knight.
Bob Willis says AB de Villiers could well be the best batsman of all time after blasting a record ODI ton off 31 balls.
As England fly off to Australia, Nasser Hussain explains why 2015 is a year to savour...
Sky Sports' cricket experts have picked their favourite hundreds from previous World Cups. Do you agree with their choices?