Qualifying at Silverstone is due to commence at 9am, and the session can be followed with live updates by clicking here.
Testing this week has been extremely close, with under a second covering the lead 16 runners on both Thursday and Friday.
Elite Motorsport's McKenzy Cresswell topped the times, setting the fastest lap of the week on Friday, recording a 1m53.274s, putting him a quarter of a second clear of the pack.
Hitech Pulse-Eight's Gerrard Xie was his closest challenger after topping the final session, with Rodin's Louis Sharp and JHR's John Bennett, both title contenders, right up there too.
Elite duo Jarrod Waberski and Hugo Schwarze also enjoyed strong runs in testing and were inside the top-six, while Fortec's Colin Queen and Hitech Pulse-Eight's championship leader Tymek Kucharczyk were firmly inside the top-10, with the latter always strong at Silverstone.
Returnee James Wharton (Fortec) and Rodin's Hungary race winner Arthur Rogeon completed the testing top-10.
Qualifying will decide the grid for races one (starting at 12.05 today) and race two, with the fastest times deciding the race one grid, and the second best times forming the race two starting order.
All three races will be streamed live and in full across the event, via the GB3 Championship live timing page, the official Facebook page and the MSV TV YouTube channel.