Robert Varey set the pace as the action began at Donington Park, topping the opening practice timesheets.
Varey set a best lap of 1min:50.332sec, beating Harrison Dessoy by 0.204s as Rhys Stephenson was third.
Aaron Silvester was fourth with Jack Smith fifth.
Pirelli National Sportbike with Moneybarn Vehicle Finance, FP1 result:
1. Robert Varey (Stanford Fastline) 1min 50.332s
2. Harrison Dessoy (Rev2Race Yamaha) +0.204s
3. Rhys Stephenson (Rocket Racing) +1.033s
4. Aaron Silvester (MIH Solutions/Macadam Racing) +1.614s
5. Jack Smith (Woodland Racing) +2.051s