I imagine The Big One would probably be in with a shout; I once timed the thrilling body of that ride experience (i.e. dropping off the lift hill to hitting the final brake run) at about 90 seconds in length!
The Big One is the UK’s longest coaster (and indeed Europe’s longest coaster) in terms of track length, with 5,497ft of track, but it’s no short ride in terms of duration either despite its tall height!
EDIT - I decided to time the “thrilling body” (from top of lift hill to hitting the final brake run, excluding parts like mid-ride lift hills) of a few of the previously suggested contenders alongside The Big One, and the results were as follows:
- The Smiler: 1m 9s (including indoor inversion)
- Icon: 1m 11s (including launches)
- Vampire: 1m 5s
- The Big One: 1m 15s
So of the rides suggested in the thread, The Big One is the longest.