Entry Requirements

Entry Requirements play a huge role in helping you decide which medical school to apply to. Here are the main aspects of it:
1.GCSE(O Levels)
2.Predicted/Achieved Grades @ A level/IB/Scottish Highers/Etc;
3.UKCAT
4.BMAT
5.UCAS Tariff(http://www.ucas.com/students/ucas_tariff/ please refer to this website for the exact information, from what i know, Queen Mary is an example of a medical school that uses this)

Different medical schools place different emphasis on different parts of your academics.
GCSEs:
Some schools require a minimum number of As/A*s(Eg: Cardiff, Birminghan,Belfast) while some use it as part of their 'scoring system' (Eg; Leicester) While some consider it only when there is a tie breaker (Eg; Dundee)
These school may change their admissions policy from year to year so please make sure you check on their websites!(http://www.thestudentroom.co.uk/wiki/Medical_School_GCSE_Requirements gives an extremely clear guide as to what is needed for each medical school)

Predicted/Achieved grades:
Since I only did A Levels, I can only speak for those taking their A levels.
Generally , your predicted grades should be at least AAA and a predicted A* would not usually matter unless you have already achieved your A*(My friend applied to Bristol and got an interview which he believes he got mainly because of his achieved A*)
If you are a gap year student, AAA would be the minimum grade that you need!

UKCAT
Just as how the GCSEs are used differently by different medical schools, the UKCAT is used in varying ways. Some use it as part of their 'scoring' method(eg:Leicester), some use it to decide who get an interview by ranking their UKCAT scores(Newcastle/Durham), some use it as a cut off, in the sense where if you have an average score about the threshold they set, your UKCAT would no longer matter(Eg; for 2013 Entry, the cut off for Sheffield was 600)
Please note that all these are based on the 2013 application cycle and may vary from year to year.

BMAT
There are only a handful of medical schools in the UK that require you to take the BMAT, unfortunately I am not really clear on it as I chose not to take it and apply to the schools that require it. I would hate to be misleading so I would suggest you read up about it on TSR to get a clear idea on how it is used and what it is about

This is about all that I  have to say about this really ! Please note(again), that all these are based on what I have heard/learnt about the medical schools from this year's application cycle and may vary from year to year! So please do your own research and ensure you are clear of your chances of getting an interview before applying!

Best of luck to you! Feel free to contact me at lovebullets1995@gmail.com !