Cammish tops FP1 before suffering shunt at Donington Park
The Ford Focus ST driver set the timesheets alight after producing a 1'33.670s lap around the Grand Prix layout. However, with the fastest time safely in his pocket, Cammish brought out the red-flag with around three-minutes to go after crashing out at the Old Hairpin.
Although it's unclear what caused the crash, the incident caused significant damage to the rear of the Motorbase Performance prepared Ford Focus.
Despite his heavy crash, Cammish ended the session over 0.4s clear ahead of the rest of the pack with Hyundai driver Tom Chilton proving 'best of the rest' after setting the second fastest time.
Championship leader Ash Sutton was third fastest aboard the sister NAPA Racing UK, 0.016s ahead of leading Toyota effort Ricky Collard in fourth.
Having endured a nightmare weekend in Knockhill last time out, four-time champion Colin Turkington will be looking to reignite his fading title hopes after falling 81-points adrift of Sutton's championship lead.
Turkington ended the opening session as the fastest BMW runner in fifth ahead of Toyota Gazoo Racing UK's Rory Butcher in sixth.
Sam Osborne enjoyed a strong FP1 run to ensure three out of the four NAPA Racing Fords made the top-ten order in seventh, while Aron Taylor-Smith, Jake Hill and George Gamble completed the remainder of the top-ten FP1 order in eighth, ninth and tenth.
Elsewhere, defending champion Tom Ingram also endured a session to forget after the rear-left wheel vacated his Hyundai i30N towards the end of the session.