Britain’s apparent determination to pursue trade talks with countries outside the EU could significantly undermine its efforts to negotiate a favourable Brexit deal and may well be illegal, diplomats and officials have warned.

Theresa May meets Donald Trump on Friday to discuss a post-Brexit transatlantic trade deal the president has said he would like drawn up “quickly”, while Australia has said talks this week should “begin to lay the foundations” of a similar pact with the UK.

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But EU officials and diplomats say that while no one can stop Britain talking to future trade partners, any concrete attempt to negotiate free-trade agreements before Britain leaves the bloc could rapidly sour Brexit negotiations.

“They do need to be careful about this,” said one London-based EU27 diplomat. “No one will object to broad preliminary talks, but anything that looks like proper negotiations … That would certainly not be well received.”

Another diplomat in Brussels said the prime minister and her trade team could “obviously have candid informal discussions”, but cautioned it would “not be constructive if the UK did engage in actual negotiations”.

The prime minister has said she intends to capitalise on Brexit by making the UK a leading global free trade champion, negotiating new agreements with countries such as the US, China, India, Australia and New Zealand.



The international trade secretary, Liam Fox, has said the UK is “discussing the possible shape of new agreements” with at least 12 countries, adding that dozens more were prepared to expand their UK trading links.

Besides the risk of antagonising the EU at a time when Britain will be seeking to strike the best possible exit deal with the bloc, formal trade talks with countries outside the EU could also be illegal until Britain leaves.

EU states cede their right to sign trade deals to the European commission in Brussels and are formally prohibited from pursuing their own agreements.

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“Under EU law, no member state discussions on trade agreements – as opposed to commercial deals, like selling planes – with non-EU countries are possible at all,” said Steve Peers, professor of EU law at the University of Essex.

However, Peers said it could be argued that “since it is leaving the EU, the UK is not fully bound by that rule at long as it does not actually conclude any treaties before Brexit day. The legal position is not certain.”

It is understood that the government’s private legal advice is that no agreements may be signed while the UK remains an EU member, but it is free to start talks as soon as Britain begins the legal process of leaving the union, which May has said it will do by triggering article 50 by the end of March.

That appears to be at odds with the EU position. “There is nothing in the treaties that prohibits you from discussing trade,” commission spokesman Margaritis Schinas stressed this week, “but you can only negotiate a trade agreement after you leave the European Union.”



Joseph Muscat, the prime minister of Malta, which holds the rotating EU presidency, said it was “very clear that in order to sign and have a bilateral agreement with third countries, the UK first needs to reach a settlement with the EU”.

The commission’s president, Jean-Claude Juncker, has said that for EU members trade talks are “exclusively a matter of the EU”, and trade commissioner Cecilia Malmström reiterated in Davos last week that trade negotiations before Britain leaves the bloc – expected to be by March 2019 – were not permitted.

It is unclear how the EU could realistically draw the line between “talks about trade” and formal negotiations. “That is impossible for us to say, and I think member states are relying on the UK’s commitment and goodwill,” one Brussels source said.

It is also unclear how much authority – and appetite – the bloc might have to stop Britain entering formal trade negotiations outside the bloc. Ultimately, the only way to obtain legal certainty on the question would be for the EU27 to bring a case before the European court of justice, Peers said.

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But if Britain may judge that unlikely, EU diplomats warned that anything that might be seen as an attempt to subvert the spirit, if not the letter, of EU law risked backfiring, at a time when the UK most needed the goodwill of the EU27.

“It would not go down at all well,” the London-based diplomat said. “There are rules, and this is one of them. Britain will have to decide: is it better to line up all these deals outside the EU but risk getting a worse deal from within the EU?”



Nick Clegg, the former Liberal Democrat leader, said it would be “understandably irritating” for other EU leaders to see “enthusiasm with which British Conservatives believe, falsely and wrongly, that a trade deal with the anglosphere could somehow match the very extensive trade we have with our neighbours in Europe”.

Clegg, a former EU trade negotiator who worked on trade talks with China and Russia, said it was “economically illiterate” to think there was some kind of trade panacea waiting for the UK outside the EU.

“There is a very good reason why Britain trades more with Belgium and Ireland than it does with Australia – Australia is on the other side of the planet.”