Honda Racing UK’s Jack Kennedy drew first blood as the Quattro Group Supersport pack hit the track at Donington Park, setting the pace with a best lap of 1min 40.226secs.
Kennedy – tied at the top of the points standings with Luke Stapleford coming into this weekend – ended FP1 1.036secs clear of defending champ Ben Currie after a damp and cloudy session.
TJ Toms was third quickest on the R&R Racing Yamaha, with Shane Richardson fourth and Rhys Irwin fifth.
It was a new leader in the GP2 class, as Keo Walker took the class top spot, with Jack Nixon second and his Kramer Racing team-mate Owen Jenner third.
Cameron Hall topped the Cup class timesheets, with Lynden Leatherland second and Lewis Jones third.
Quattro Group British Supersport & GP2/HEL Supersport Cup, FP1:
1. Jack Kennedy (Honda Racing UK) 1min 40.226s
2. Ben Currie (Oxford Products Racing Ducati) +1.036s
3. TJ Toms (R&R Racing) +1.055s
4. Shane Richardson (Astro-JJR Hippo Suzuki) +1.779s
5. Rhys Irwin (Gearlink Kawasaki) +2.022s