Bradford rider Dean Harrison knocked Michael Dunlop off the top of the Classic Superbike leaderboard during Thursday's red-flagged practice session on the Isle of Man.

Harrison lapped at 123.580mph to set the fastest time of the week so far on the Silicone Engineering Kawasaki.

The session got underway promptly at 6.20 and Michael Rutter on the Harris Yamaha was first to the first timing point at Glen Helen, three seconds ahead of Harrison. The Midlands-based rider had extended that to almost six seconds by Ramsey but was reported to have retired shortly after at the Waterworks, leaving Harrison to top the board with his opening lap.

Bruce Anstey also completed his first lap on the Valvoline Racing by Padgetts Motorcycles YZR 500 at 121.18mph while Danny Webb (120.12mph) clocked his first 120mph lap of the meeting on the Team Classic Suzuki XR69.

Gary Johnson (Team York Suzuki) and James Hillier (Greenall Racing Kawasaki) both moved into the overall top five leaderboard in the Superbike class with impressive opening laps of 122.56mph and 122.12mph respectively, while Jamie Coward on the Mistral Racing Kawasaki also posted his first 120mph lap of the meeting.

Meanwhile Michael Dunlop, after some chassis changes, was slower than he has been this week with his opening lap of 120.51mph on the Team Classic Suzuki XR69.

In the Lightweight class, Manx rider Ryan Kneen posted the fastest lap of the class on the night with a lap of 111.63mph and moved into the top three overall in qualifying, behind Ian Lougher's time from Tuesday and Bruce Anstey's from Wednesday.

With riders in both classes still circulating on the course the session was red-flagged from sectors 1 to 8 following an incident at Churchtown on the approach to Ramsey in the concurrent Manx Grand Prix qualifying session and the session was brought to a halt shortly before 6.45pm.

Unfortunately, while the road was being swept ahead of the Classic TT Junior and Senior Classic TT session, the mist came in on the mountain section and Clerk of the Course Gary Thompson ended the session at 7.20pm.