As someone said it's expensive, it'd far more easier to secure a contract.
However if you have spare time and a spare grand you could do the 6 knowledge stage exams yourself. It's recognised as some sort of Business Certificate now and is a tool for people without the academic criteria to get onto chartered.
If you have no accounts knowledge it would be best to do Accounting knowledge at college, that'll probably cost you around £600 all in. You could do the other 5 teaching yourself (I think one of the big 4 is doing self-study next year anyhow). I would've given you the materials for free but I chucked them (I really enjoyed tearing those manuals), but you can contact that lad who's selling them. Each knowledge exam is around £60 - £70 and the sittings are fairly flexible, they've got something with Parsons Vue so you can sit them at your local driving theory test place if closer than college.
As for registering with the ICAEW you'll have to pay some sort of student subscription, probably around a couple of ton for the year, but I could be wrong.
You can sit 14 out of the 15 exams independently, the Case Study can only be sat in your final year of contract and you need to be on a recognised contract.
Hope that helps, if you don't get a contract don't fret, you could always do a few knowledge papers so a potential employer will at least think you have the desire. Different qualification but I know a few people who work temp jobs and put themselves through ACCA, they are the real accountancy warriors.