Filip Surowiak took control in second practice at Donington to bank a 1min 40.777sec lap to lead the way at the end of day one.
The Team City Lifting/RS Racing rider was 0.162secs clear of Harley McCabe, as Lucas Brown ended the day third.
Fourth quickest was Ryan Frost as Alexander Rowan rounded out the top five.
R&G British Talent Cup, Combined practice:
1. Filip Surowiak (Team City Lifting/RS Racing) 1min 40.777s
2. Harley McCabe (Fibre Tec Honda) +0.162s
3. Lucas Brown (SENCAT Talent Team/Mortimer Racing) +0.241s
4. Ryan Frost (Fibre Tec Honda) +0.415s
5. Alexander Rowan (Alexander Rowan Racing) +0.820s