Richard Kerr took control in opening free practice at Donington Park as he clocked a best lap of 1min 29.103s to lead Alex Olsen by 0.295s.
Alistair Seeley finished the session third, 0.291s behind Olsen with Dan Linfoot fourth and Lewis Rollo fifth.
Pirelli National Superstock with Santander Consumer Finance, FP1:
1. Richard Kerr (AMD Motorsport) 1min 29.103s
2. Alex Olsen (Cumins by Team IWT Honda) +0.295s
3. Alastair Seeley (SYNETIQ BMW Motorrad) +0.586s
4. Dan Linfoot (Optimum Bikes Racing Ltd) +0.935s
5. Lewis Rollo (IN Competition/Aprilia) +1.076s