Many of the services previously provided from London cannot be provided from without the Single Market, which will require London-based banks and law firms to establish permanent establishment with the EU-27. The British tax havens see new market possibilities in China, India, the Middle East and Africa.
But this will probably involve laundering ever larger amounts of dirty money and enabling ever more tax avoidance. Britain has failed to plan for industrial diversification for decades and now faces limited development options.
The British economy is heavily reliant on external trade in services which is dominated by financial services. Any shock to the financial services sector, for example arising from being denied access to the EU Single Market, would be highly damaging to the economy.
Britain has consistently voted against creating a globally representative inter-governmental body to shape a framework of rules to strengthen international cooperation on tax matters. Britain has successfully resisted international pressure to take effective action against its tax havens in the Channel Islands, the Cayman Islands, the British Virgin Islands, and other British dependencies.
I have observed British officials blocking attempts to strengthen international cooperation on tax information exchange by keeping discussion on offshore trusts off the agenda. This happened as recently as 2015 when Prime Minister David Cameron pushed to have trusts excluded from information exchange processes. This is a pivotal issue since offshore trusts are key to the British tax haven secrecy model. Britain has also spent years blocking EU attempts to make progress towards a common approach to taxing multinational companies (the Common Consolidated Corporate Tax Base).