Firstly, let me explain that I am a current trainee at one of the magic circle law firms.
Secondly, although what I say will be based on opinion, I will try to include as many facts as possible.
Having not only met the hundred or so people in my training intake, I have also met a large proportion of the intake for a couple of other magic circle firms. Mainly because we were all at the college of law together doing the LPC and partly because, having studied law at one of the main London universities, I have ended up with a lot of friends going to different firms.
My advice would be to take any recruitment website, prospectus, talk (or any HR promotion) with a pinch of salt. They will always do their best to show that their firm is the most diverse in terms of (i) class, (ii) race, (iii) academic background, etc.
That is not to say that some firms aren't any of the above, but when they all sing the same song - it's almost impossible to see the truth without actually spending time there (or knowing someone who has).
From what I have seen, magic circle firms (and mine in particular) mainly take from these universities:
Oxford / Cambridge / LSE / UCL / Durham / Bristol / Manchester / KCL
[no particular order at all].
On occasions you can find people coming from different universities (such as Southampton, Warwick, Nottingham), albeit by and large the lawyers come from the list above.
Ultimately, RANKINGS DO NOT MATTER. They fluctuate yearly and TBH I doubt that HR have time to consider the subtle nuances between universities from year to year.
Provided you graduate from a top university, then you have crossed the first hurdle (of many).
What is more important in getting a TC at a magic circle firm (or any firm for that matter) is that you:
1. write a coherent and impressionable vacation scheme/TC application,
2. gathered relevant work experience,
3. demonstrate enthusiasm and commitment in extra curricula activities,
4. are knowledgeable about the commercial factors which surround legal issues,
5. perform well in the interview,
6. (and above all) are passionate about whatever area of law in which you wish to practise,
If you have done all of the above, your university will be an important factor - but by no means will it be the determinative factor.
On a side note, I have done *a lot* of graduate recruitment events for my firm including opens days, talks etc. The BEST advice I can give you all is to do well in your degree - wherever you are. If you get a 2.2 or below then it's game over. Many of top 30 firms require a 2.1 as a minimum - and DO NOT think that a 2.2 with a Masters will save you. A Masters is not there to allow you to sweep a lower undergraduate degree under the carpet - HR are not stupid. Unless you have a good reason, a Masters cannot save you so please stop asking!
Also, though this is mainly my personal opinion (based on my experience), QM is not a strong university for law. There has been a lot of talk on this thread that it is equally as strong, or thereabouts, as the other London universities. It isn't. I have never met someone from a top firm from QM (though not to say there isn't). If you look at the special open days firms exclusively hold for particular universities - QM is not one of them. Furthermore, my firm did not even make an appearance at the QM law fair - and since I have a friend from another firm who did attend - I know that only one magic circle firm bothered to turn up, and in total there was only 15 firms in a small room. Not an impressive turn out, unfortunately that may be quite indicative of QM's status in the eyes of HR.