It is very applicable to the UK. sixesandsevens document is a good start, but note that there is a whole world of online platforms now (Hargreaves Lansdown, Bestinvest, etc) which can be much more convenient and give you more control.

Note that there is SDRT of 0.5% on UK equities, which you will likely pay as a secret hidden tax on your index fund - the more ethical companies, such as Vanguard, make this clear - so you may wish to choose your index fund to avoid this pernicious tax. If you work in the UK, you are probably implicitly overexposed to the UK economy anyway, so this is an argument to track a global, non-UK stock index.

Most of the information on index funds that has been provided in this thread, and in links from this thread, is applicable to the UK. I suspect all the information you're likely to retain, and need, is applicable.

Here is a quick-and-dirty document I threw together for London LWers looking to invest in index funds but not knowing where to start. There are better guides out there but they are necessarily longer. Googling "UK index tracker" will get you quite far.