Any thoughts on which is a reliable exchange either based in the UK, or that is happy to accept GBP?

So if I'm just 'buying' bitcoins this is potentially the only dodgy part? ie. if the exchange goes bust while I wait for my order to be matched.  Can this take a while as it looks for a match, or is it basically like trading shares where there's pretty much always someone selling (or the exchange acts like a marketmaker, and has a certain number itself to trade with?)

Hi,

I'm completely new to this so apologies for the basicness of these questions. This is my understanding so far...

• So as far as I can tell the "wallet" sits on my PC with my bitcoins in and is secure.
• I can accept money into and pay money out of my wallet directly to/from someone else.
• If I want to 'buy' bitcoins with my local currency then I need to do this via an exchange.

Assuming that my understanding is correct how am I affected if an exchange goes bust or shuts down?  For example, I read about the MtGox thing where apparently a lot of bitcoins went missing or were stolen or whatever - but basically people got screwed out of their bitcoins.  So if an exchange is just a place to exchange bitcoins with other currencies how did people lose their money?  I would assume that once the transaction had gone through the bitcoins would be in the peoples wallets so they would be safe...?  Or were people somehow 'storing' bitcoins at the exchange? Or did the people that lost money just happened to be in the middle of the transaction when MtGox shutdown (so they took the cash, but didn't send the bitcoins)?

I just want to try and understand how they lost the bitcoins when that happened as, from my basic understanding, it doesn't seem to make any sense?