Brookes edged out triple champion Shane 'Shakey' Byrne to claim the top spot at the top of the timesheets in the opening session on track, waiting until the closing stages to displace the Rapid Solicitors Kawasaki rider.
Chris Walker maintained his momentum from the Lloyds British GBmoto Racing Kawasaki's recent test in Spain to end the session third fastest ahead of triple champion Ryuichi Kiyonari as he quickly slashed his lap times on the Buildbase BMW, equalling the time of Jakub Smrz on the Millsport Ducati.
Tommy Bridewell was sixth fastest on the second of the Milwaukee Yamahas as he pushed ahead of James Westmoreland on the Buildbase BMW and James Ellison on the second Lloyds British GBmoto Racing Kawasaki. Stuart Easton and Richard Cooper completed the top ten, with John Hopkins waiting until the afternoon session to get out on track onboard the Tyco Suzuki.
MCE British Superbike Championship, Donington Park, official test, morning sessions:
Josh Brookes (Tyco Suzuki) 1m:31.226s
Shane Byrne (Rapid Solicitors Kawasaki) +0.162s
Chris Walker (Lloyds British GBmoto Kawasaki) +0.944s
Ryuichi Kiyonari (Buildbase BMW) +1.091s
Jakub Smrz (Millsport Ducati) +1.091s
Tommy Bridewell (Milwaukee Yamaha) +1.266s
James Westmoreland (Buildbase BMW) +1.318s
James Ellison (Lloyds British GBmoto Racing Kawasaki) +1.386s
Stuart Easton (Rapid Solicitors Kawasaki) +1.573s
Richard Cooper (Anvil TAG Hire Kawasaki) +1.652s