Bank of England tests have flagged up some serious Brexit concerns.
Six million UK customers buy insurance policies from EU companies and, after Brexit, those firms would not have permission to collect premiums or pay claims.
The same is true of the financial insurance that banks buy and sell to each other. Here the numbers are staggering - the notional value of those contracts are £26 trillion. Without legislation from both the EU and the UK they may be hard to enforce and that would create financial instability.