Lee Johnston beat Tom Toparis to free practice one bragging rights with a best lap of 56.338secs.
The Ashcourt Racing rider held a 0.092s advantage over Macadam Racing’s Toparis as Tom Booth-Amos ended the session third on the Gearlink Kawasaki.
Astro JJR Suzuki’s Jamie Perrin was fourth quickest, as Dutchman Jamie van Sikkelerus ended the session fifth.
In GP2, Joe Collier led the way, 10th overall with Cameron Fraser second and Harry Rowlings third.
Quattro Group British Supersport/GP2: FP1
1. Lee Johnston (Ashcourt Racing) 56.338s
2. Tom Toparis (Macadam Racing) +0.092s
3. Tom Booth-AMost (Gearlink Kawasaki +0.198s
4. Jamie Perrin (Astro JJR Suzuki) +0.252s
5. Jamie van Sikkelerus (MPM Routz Racing Team) +0.273s