I know two people who failed.
One person failed because they were using the question/answer bank from the previous year.

I think although they give you 1 hour to do the exam, it should only take you about 10 mins really.
(witty_ditty has made multiple miaows since, Thu 20 May 2004, 17:33, archived)

I can trump you....
I know someone who failed their theory test THREE, yes THREE times, then somehow managed to pass practical test 1st time.
(wobblyjelly, Thu 20 May 2004, 17:36, archived)

But - how?
Some things, I guess, like marmite, and quantum physics, are just beyond comprehension.
(witty_ditty has made multiple miaows since, Thu 20 May 2004, 17:41, archived)