Take an obvious and very direct example. Cleaning staff. Not having to compete with EU illegal immigrants will improve their labor conditions. Building workers and Polish guest workers who send all money back home and live in extremely poor conditions, same. Yes that probably means the next time you need your toilet repaired, you'll pay more, but you'll pay more so the plumber can have a better life.
Even for tech startups, this may be an improvement. I know over 4 London-based startups that don't directly sell to customers. They "consult" for a foreign entity (a US company in 50% of the cases, other 2 use Asian proxies), which then sells to EU customers because selling digital products to EU customers from outside of the EU is far cheaper and simpler than doing it from inside the EU.
One thing I absolutely do not get is why socialists and even those left-inclined are so massively pro globalization. That just makes no sense whatsoever. There are constant complaints about globalization here. How Monsanto/Big finance/Suez/... convinced congress/EU/ECB/... that X is going to happen/be legal which means state/city/even small town Y gets shafted in Y way. For once, that becomes a little harder.
But yes, it's probably the wrong thing for center London tech and finance workers and managers.
The EU is reacting, imho, in the worst possible way. The press in France, Netherlands and Belgium is full of articles on how it was stupid, boneheaded, evil, weak for Cameron to allow the vote in the first place. It's generally all being blamed on Cameron, and his mistake is allowing people to vote in the first place. Very EU, being so overtly anti-democratic.
But let's face facts here: the EU will try to make this work the same way the other referendums worked [1][2]. When the votes turned against the EU, they canceled the rest of the voting ("postponed" the term used, but they never happened). And then they cheated (the referendum happened because the law said it should happen before the law was changed. The law was changed without referenda). So I'm giving the odds of a Brexit happening at best 30-40%. Granted, that's far better odds than I gave it yesterday, so maybe I'll be wrong again. But the EU has a long history of ignoring democratic votes.
The sky is not falling, this is not the worst thing to ever happen, and frankly, the market is wrong. This is a massive overreaction.
[1] https://en.wikipedia.org/wiki/French_European_Constitution_r... [2] https://en.wikipedia.org/wiki/Dutch_European_Constitution_re...