The UK could call on just 25 people to negotiate a 'Brexit' deal when hundreds of specialists are needed, a leading international trade lawyer has warned.
Miriam González Durántez, a partner of the Dechert law firm, says the UK would need "at least" 500 negotiators working for many years to re-cast the country's relationship with EU member states and countries the bloc has existing deals with.
The lawyer, who is married to former Lib Dem leader Nick Clegg, told The Huffington Post UK the UK was poised to "re-negotiate absolutely everything".
She said: "The UK is not going to be able to re-negotiate in the short-term to get the same level of trade protections the UK has now under the EU.
"The only practical way forward is to prioritise only a few agreements - up to seven. Otherwise this is un-doable."
Her intervention comes as Boris Johnson - seemingly the Brexit-er-in-chief -gave the first hints of how life outside the EU should look in his weekly column for The Daily Telegraph.
While Johnson said Britain would always be "part of Europe", he argued there would be "access to the single market". Many interpreted "access" as being outside the existing trading zone but with bi-lateral deals with members of it. Key Leave campaigner, Ruth Lea, appeared to agree.
And 'Brexit' Tory MP and minister Andra Leadsom hinted as much.
Though not everyone saw it like that.
González Durántez says being in the EU means the UK can take advantage of 80-plus EU trade agreements in force or being formalised.
On top of that, there are deals with 15 countries - from the US to Brazil and Japan - in the pipeline.
She argues the lure of trading with 67m consumers in the UK compared to 500m customers in the EU means it is "only natural" countries will want to renegotiate with 'Brexit' UK for more favourable terms.
González Durántez believes remaining within the single market - the "straight-forward option" - has been dismissed: "This campaign was based on the premise there would not be free movement of people. That would mean going back to the people and saying the main thing I promised to you is not going to happen."
She added: "If you don't have the single market under the EU then you need to re-negotiate absolutely everything. From competition, privacy, consumer protection, financial services. The whole thing. So you need a team fully dedicated to that."
And does the UK have that? "It isn't that UK officials are not clever enough to do it. Of course not. But they don't have the training. They haven't had the competence for a long time. They need to get to grips with it.
"And they need to do, as quickly as possible, something that has taken years in the EU. Forty years doing this. And they need to do it all at the same time."
The 25 figure is based on British citizens currently doing the role in Brussels - and some may be working on obscure aspects of deal-making, she says. The lawyer added the estimate of needing 500 experts was "cautious": "It is likely to be many, many more."
Her concerns were first detailled in a column for The Financial Times in May. The Lib Dems, now led by Tim Farron, have said they will campaign to return the UK to the EU.
