A lot of your questions have been answered by the poster right before me, but I just wanted to add my two cents in regarding your concerns about being accepted to the best law programmes in the UK.
My own experience comes from having done the Graduate Diploma in Law (GDL) in the UK, as I did not do law as an undergraduate (I did a degree in International Relations). In terms of the application for the GDL, which is what the overwhelming majority of non-law undergraduates do (it is commonly referred to as a 'law conversion course'), it is much, much less intensive than applying to US law schools. The most common places to study the GDL in the UK are either at the College of Law (which has numerous campuses throughout the UK, including two in London), or at BPP (in London). If you intend on pursuing the barrister route, which as the previous poster mentioned is exceptionally difficult, you may want to look at doing the GDL at City University (in London). In any case, you must apply for the GDL through the Central Applications Board (
http://www.lawcabs.ac.uk/). If I recall correctly, you need to provide two letters of reference and need to complete a very brief statement of intention. It is worth noting that both the College of Law and BPP are private institutions, unlike all other UK universities, and while they have degree awarding powers, this financial incentive for them means that as long as you have decent undergraduate marks, you will be accepted. In my experience, I've never heard of anyone being denied entry to the GDL. There is no home-fee/international fee difference at CoL/BPP, everyone pays the same rate. This isn't true at City, where you will pay a bit more as an international student (even if you have EU citizenship, it is my understanding that you have to demonstrate that you have been resident in the EU for three years preceding the commencement of the course in order to qualify for 'home-fees'). On the GDL you will study seven core areas of law (Contract, Criminal, Land, Equity & Trusts, Tort, EC Law, and Public Law) and you will have to complete a brief Legal Method module. There are no electives to choose from at this stage.
Once you have completed the GDL (if you go down that route), you will need to either complete the LPC (if you want to become a solicitor) or the BPTC (if you want to become a barrister). You might want to look at the steps required to become a solicitor advocate, which is essentially a solicitor-barrister hybrid that is gaining in popularity (essentially, they are trained as solicitors but have rights of audience, which means they can represent clients in court). If you are concerned with the expense of completing the GDL and the LPC, one GREAT thing about the UK legal system is that you can get your future law firm to pay for your tuition fees for both the GDL and the LPC, and some will even give you a stipend for your years of study. It's a bit of an odd system, but once you complete the GDL and the LPC, you will have to do two years of on-the-job training, known as a training contract (you get paid for these years). Most law firms award training contracts two years in advance, but once you secure a training contract, most firms (certainly the large, international ones) will pay for your tuition fees. Thus, you enter into law school with a guaranteed job at the end of it, and your fees are paid.
If you want to go down the BPTC route, things are a bit different. After you do the GDL, you would go on to the BPTC. After that, you would do a one year pupillage with a barrister's chambers (also called a set). Gaining pupillage is exceptionally difficult. To give you an idea, each year in the whole of the UK only about 1500-1700 students enroll on the BPTC (only the best and the brightest, with the most outstanding 'extracurriculars', bother enrolling). Out of that pool, fewer than 500 ever gain pupillage. The year of pupillage is known to be incredibly rough--for starters you will be at your chamber's beck and call (working very long hours) and are likely to only be paid 10,000 pounds for the whole year. Some chambers offer more money for the pupillage year, but in my experience, it's usually people who have been very successful in another career and have then decided to become a barrister that manage to secure the pupillages that pay more. In any case, once you have done your pupillage year, you still need to secure tenancy at a set. If you do manage this, you truly start your career as a barrister. Technically, barristers are self-employed (even though they form chambers or sets, primarily to share costs and share clerks, etc) and thus what you earn is largely down to how good you are, and the reputation you create for yourself. In terms of paying for the GDL/BPTC, your best bet is to apply for a scholarship with one of the 4 Inns of Court (Gray's Inn, Lincoln's Inn, Middle Temple or Inner Temple). However, chances of securing a scholarship to pay your fees are much lower than if you want to be a solicitor and find a law firm to pay.
You can find a lot of information about the different law firms and different chambers on
http://www.chambersstudent.co.uk/ which is quite a comprehensive website. If you have any further questions, don't hesitate to ask!
