AFAIK in UK, for example, it would require a budget of at least half a million £ to set up an organisation which can legally trade as a BTC exchange or BTC options market maker, clearing house etc... ( i.e. when you take someone's money as deposit or collateral). Requirements to qualify for FSA license are not easy to meet.
I would bet that for this reason (in UK) before a new company formed to act as a securities broker in bitcoins an established broker will add some bitcoin based instrument to the market.
On the other hand, there should be no problems if someone just sells his BTC's, even as futures or option contracts i.e. otc trade. BTC is not much different from let's say wheat in this regard. These are just regular contracts.
I looked into this too, and I found the same as Vladimir, although I think you could meet FSA requirements for a bit less, maybe £200,000.
The UK does not have the same "bottom-up" entrepreneurial environment that, say, the US does. So new technologies are most often introduced by some existing big company deciding to branch out into the new field. And often they need to get the regulations rewritten to make it possible. The BBC and PayPal, amongst others, did this but it's not possible for the "little guy" to do the same.
For this reason, none of the big internet technologies were developed in the UK. None the new business models (as exemplified by eBay, Amazon, CraigsList, PayPal, Google, YouTube, Flickr, etc) originated in the UK, even though the UK makes up a large percentage of internet users.
The best we did in the UK was a couple of websites that started selling last minute holidays, or listing real estate online. And all of today's big UK internet sites are divisions of pre-internet businesses (e.g. the BBC, or newspapers, or bricks-and-mortar retailers).