Sam Tordoff topped the British Touring Car field after two disjointed free practice sessions at Croft.
Tordoff's Triple Eight MG had just recorded two times good enough to lead the way in the second session when Rob Austin's Audi crashed at Clervaux and brought an early end to the session.
The MG's best of 1m24.115s is more than 0.3s faster than Colin Turkington's 2013 pole time.
Reigning champion Andrew Jordan was second, having been quickest for much of the second, faster, session in his Eurotech Honda Civic with an early run of 1m24.390s.
Turkington had led the way in the first session, which had been affected by both a red flag (to retrieve Aiden Moffatt's Chevrolet) and rain, with 1m24.498s.
The WSR BMW driver failed to improve in the afternoon session, but his earlier time was good enough to put him third overall.
Third in the second session, and fourth overall, was Adam Morgan's Ciceley Mercedes. The A-class was competitive in both sessions and ended up with a best of 1m24.763s.
Fifth was the ever-improving United Autosports Toyota Avensis of former British GT champion Glynn Geddie, while Austin rounded out the top six despite his crash.
Gordon Shedden (works Honda Civic Tourer), Alain Menu (BMR VW CC) and Martin Depper (Eurotech Civic) were next, and Dave Newsham rounded out the top 10 with the AmD Ford Focus, which has an upgraded front-end this weekend.
Former double champion Jason Plato's running was limited by "something underneath" his MG6, but he expects the car to be fine for qualifying.
Pos Driver Car Time Gap Laps
1. Colin Turkington WSR BMW 1m24.498s 11
2. Andrew Jordan Eurotech Honda 1m25.003s +0.505s 11
3. Adam Morgan Ciceley Mercedes 1m25.561s +1.063s 11
4. Nick Foster WSR BMW 1m25.843s +1.345s 11
5. Jason Plato MG 1m25.860s +1.362s 12
6. Sam Tordoff MG 1m25.875s +1.377s 10
7. Glynn Geddie UA Toyota 1m26.371s +1.873s 16
8. Tom Ingram Speedworks Toyota 1m26.410s +1.912s 15
9. Matt Neal Honda 1m26.417s +1.919s 9
10. Alain Menu BMW VW 1m26.448s +1.950s 7
11. Martin Depper Eurotech Honda 1m26.523s +2.025s 7
12. Mat Jackson Motorbase Ford 1m26.548s +2.050s 13
13. Hunter Abbott RAR Audi 1m26.629s +2.131s 15
14. Aron Smith BMW VW 1m26.888s +2.390s 18
15. Gordon Shedden Honda 1m26.914s +2.416s 9
16. Dave Newsham AmD Ford 1m27.332s +2.834s 15
17. Dan Welch Welch Proton 1m27.615s +3.117s 17
18. Jack Goff BMR Vauxhall 1m28.249s +3.751s 12
19. Ollie Jackson Welch Proton 1m28.370s +3.872s 17
20. Rob Collard WSR BMW 1m28.620s +4.122s 9
21. Warren Scott BMR Vauxhall 1m28.687s +4.189s 13
22. Chris Stockton BTC Chevrolet 1m28.885s +4.387s 18
23. Rob Austin RAR Audi 1m29.875s +5.377s 4
24. Robb Holland Rotek Audi 1m30.548s +6.050s 15
25. Lea Wood Houseman Toyota 1m30.914s +6.416s 14
26. Marc Hynes MG 1m31.083s +6.585s 14
27. Fabrizio Giovanardi Motorbase Ford 1m31.794s +7.296s 9
28. James Cole UA Toyota 1m35.819s +11.321s 13
29. Jack Clarke Motorbase Ford 1m36.185s +11.687s 13
30. Simon Belcher Handy Toyota 1m39.267s +14.769s 13
31. Aiden Moffat Moffat Chevrolet No time set 0
Pos Driver Car Time Gap Laps
1. Sam Tordoff MG 1m24.115s 13
2. Andrew Jordan Eurotech Honda 1m24.390s +0.275s 12
3. Adam Morgan Ciceley Mercedes 1m24.763s +0.648s 13
4. Colin Turkington WSR BMW 1m24.832s +0.717s 10
5. Glynn Geddie UA Toyota 1m24.846s +0.731s 13
6. Rob Austin RAR Audi 1m25.045s +0.930s 10
7. Gordon Shedden Honda 1m25.046s +0.931s 10
8. Alain Menu BMW VW 1m25.139s +1.024s 11
9. Martin Depper Eurotech Honda 1m25.142s +1.027s 12
10. Dave Newsham AmD Ford 1m25.185s +1.070s 10
11. Aron Smith BMW VW 1m25.361s +1.246s 13
12. Matt Neal Honda 1m25.389s +1.274s 13
13. Rob Collard WSR BMW 1m25.450s +1.335s 11
14. Warren Scott BMR Vauxhall 1m25.599s +1.484s 14
15. James Cole UA Toyota 1m25.628s +1.513s 12
16. Fabrizio Giovanardi Motorbase Ford 1m25.689s +1.574s 12
17. Nick Foster WSR BMW 1m25.738s +1.623s 11
18. Jack Goff BMR Vauxhall 1m25.863s +1.748s 13
19. Tom Ingram Speedworks Toyota 1m26.098s +1.983s 11
20. Hunter Abbott RAR Audi 1m26.237s +2.122s 11
21. Mat Jackson Motorbase Ford 1m26.310s +2.195s 11
22. Lea Wood Houseman Toyota 1m26.343s +2.228s 14
23. Marc Hynes MG 1m26.872s +2.757s 15
24. Jack Clarke Motorbase Ford 1m27.186s +3.071s 15
25. Ollie Jackson Welch Proton 1m27.293s +3.178s 9
26. Dan Welch Welch Proton 1m27.865s +3.750s 12
27. Chris Stockton BTC Chevrolet 1m27.652s +3.537s 5
28. Simon Belcher Handy Toyota 1m82.448s +4.333s 13
29. Robb Holland Rotek Audi 1m28.526s +4.411s 14
30. Aiden Moffat Moffat Chevrolet 1m34.354s +10.593s 5
31. Jason Plato MG No time set 5