The theory test is in two parts, both of which must be passed at the same attempt. The test is taken on a computer at a designated test centre. In Aldershot, the Theory test center is in Pickford Street (behind the Sorting Office). The computers are "touch screen" for this part which now contains 50 questions with multiple choice answers. 43 or more must be correctly answered.
After a short break, the hazard perception test starts. This test contains 14 video clips, each lasting about 1 minute and containing at least one "developing hazard". Click the mouse button as soon as you see any hazard developing. If you click as soon as the hazard starts to develop, you will score 5 points, reducing to 0. The maximum score is 75 and a score of 44 is currently required to pass. There is no limit to the number of clicks you make but the computer will interpret clicks in a regular pattern as an attempt to cheat and reduce your score to zero!
There are many CD-ROMs available to practice the questions and hazard perception. The DSA's DVD on Hazard perception in recommended viewing as the DSA are the ones who set the test! Video clips are reviewed showing where to look, when to click and what to click for. I can recommend others.