Number one (and the simplest reason) we simply aren't ready to mitigate the impacts.
Source: I work in Whitehall.
Number two: there will be friction at our borders were previously there was none. This will have a huge impact across a wide variety of just in time industries (affecting jobs, health of the economy, what is stocked in our shops etc)
Number three: we wont have access to European tools and databases that are hugely important in fighting crime.
Number four: Our soft power around the World has already been devastated. British diplomats around the World no longer have the influence they once did.
Number five: Our economy is really exposed to currency fluctuation. Our pound will be worth less.
Number six: We dont have the stockpiling capabilities to ensure the same level of access to medicines.
There are so, so many things that will be worse.
Number one: we are getting there....
Source: I do work for the cabinet office.
Number two: there will be friction, but it goes both ways and is in no one’s interests to exacerbate.
Number three: the EU will not have access to U.K. databases and intelligence, so a deal will be done.
Number four: our soft power around the world will come out of the EU shell and continue to do what it is good at.
Number five: the pound may be worth less, is this good or bad for exports ?, the BoE always wanted to reduce the value of the pound anyway.
Number six: we export medicines to the EU, I’m pretty sure that common sense will prevail.
There are so many things that will just carry on as normal......