You will need to bring your photo-card driving licence to the test.
If you have an old-style paper licence you will need to bring your signed driving licence along with a valid passport. The DVSA are very strict with this and will not accept any other forms of photographic identification.
It is extremely important to note that your theory test will not go ahead if you do not bring the right documentation with you to the theory test. If you do not have these required documents then you will have lost your theory test fee and can not claim it back.
To make sure that you are fully prepared for your theory test make sure you have an official revision tool, with all of the official DVSA revision questions, such as DTS Anytime an online solution which you can use on your smartphone, tablet or computer.