Since the recent changes, grades are now numbers, as opposed to letters. These range from 9 to 1, with 9 being the highest possible grade to reach.
A mark of 9 is the modern equivalent of an A*, and is reserved for the most outstanding exam results, usually those within the top 10 per cent nationally. Anything above a 5 is considered to be a ‘good pass’, with this being the same as a C grade was previously. Anything below a 5 is still considered to be a pass, but is not as prestigious as the higher numbers.
U grades are still possible at GCSE level, and are the only grades considered to be a ‘fail.’ However, it is very rare for these to be awarded, so if you get around 10 per cent of the marks available, you should generally be okay.