Question: Totally basic question, but I'm clueless :(.

How do I buy stocks (I'm based in UK)? I want to buy shares of index funds.
[Vanguard in the U.K.](https://vanguard.co.uk) offers following options:

* Invest directly - minimum £100k required per fund (I'd need at least 500k for a portfolio of 5 funds)
* Invest through a platform (I guess this is what I'm looking for?)

What would you recommend?

Is registering with an online brokerage a good way to do that?

**Edit:**
Follow-up question: From what I've read online brokerage holds my shares electronically.
What would happen to the shares and other securities if the company (broker) went bankrupt?

Answer: 
It's the only way. Vanguard UK will not let *you* invest directly. 
So you'd need to decide among the brokers who handle retail investors. [Schwab](http://www.schwab.co.uk/public/schwab-uk-en) is among those who have a UK presence.
You don't buy shares of index funds you invest your money in them, a subtle difference.
There are other low cost index funds that would be suitable for you such as the HSBC ones
<http://www.assetmanagement.hsbc.com/uk/advisers/funds-in-focus/indextrack_fund.html>

These have very low fees which are comparable to those of vanguard but without the large minimum holdings.

For the follow up question, the shares are held in trust for you and there is no risk to them if the broker went bankrupt. However there is the (small) risk of fraud of the broker using clients money/shares inappropriately (as may have been the case with MF Global (The Case is ongoing)).