You could say who your expert is, Ug
I just picked the first result I saw and thought it likely to be trusted coming from the BBC 
I could find some academic papers on the subject... but who reads academic papers..
I agree to an extent with your Barcelona think tank about government sources of finance, but I'm not sure how we solve the problem of the UK economy being mostly service based and the huge disruption to services that will be caused by Brexit.
Sir Ivan Rogers in his latest speech.
Start
The implications of this for U.K. services firms, above all, is one of many dogs which has yet properly to bark in this process. But bark it will, when it becomes apparent to the private sector that continuities they wrongly thought were close to laws of nature will disappear at the end of 2020.
I find that firms are only now just waking up to the huge implications on professional mobility.
And much of the UK services sector still harbours hopes that, having essentially been forgotten or ignored by two successive Prime Ministers to date, their interests will, to some degree at least, be catered for in any FTA. I fear they will be sorely disappointed: because the EU has simply no intention of offering more here to an ex member than it does to other major third countries.
De facto, the last 2 U.K. Prime Ministers are arguing for a “no deal” on services.
And that’s on ALL services, not just financial services, on which the financial stability case for divergence is demonstrably stronger. We actually export far greater volumes of non financial services. And the EU is massively our biggest market for those services.
Ministers just do not ever want to tell businesses that is actually what they are doing, or tell the public why it’s a great idea.
End
You have to read the whole speech really...
policyscotland.gla.ac.uk/ghost-of-christmas-yet-to-come-brexit-lecture-full-text/
And according to the trade experts I follow, selling services to the rest of the world is extremely difficult because they all have their own service industries to protect...