Theresa May is to hold talks with German chancellor Angela Merkel amid growing impatience among EU leaders at the UK’s reluctance to spell out its goals in the Brexit negotiations.

The two leaders will meet in Berlin on Friday ahead of a speech by the Prime Minister in Munich on Saturday on Britain’s future security relations with the EU.

But with talks opening last week on the second phase of the Brexit negotiations, she is facing demands from leaders of the remaining 27 member states to set out what sort of wider relationship she wants – including on trade.

On Wednesday a spokesman for Mrs Merkel said the British needed to come forward with concrete proposals, adding that “time is running out”.

It followed reports she had mocked Mrs May’s negotiating approach at last month’s World Economic Forum at Davos, complaining every time she asked her want she wanted, the Prime Minister replied: “Make me an offer.”

Brexit
Michel Barnier has warned that a transition deal is ‘not a given’ (Stefan Rousseau/PA)

The latest German intervention echoed similar warnings from the EU’s chief negotiator Michel Barnier who said last week that a transition deal – which the Government is hoping to wrap up by the end March – was “not a given”.

He said there were “substantial” differences which had to be overcome if they were to agree transitional arrangements after the UK leaves in March 2019 to avoid the “cliff-edge” break which many businesses fear.

He also warned the return of border checks between Northern Ireland and the Republic was “unavoidable” if the UK pressed ahead with plans to leave the single market and the customs union – something ministers insist they do want to happen.

In setting out her negotiating aims, however, Mrs May has been constrained by the need to hold together her Government and her party which remain bitterly divided over what kind of post-Brexit arrangements they want.

In a keynote speech on Wednesday, Foreign Secretary Boris Johnson said Britain would be “mad” to accept a deal which did not allow it to capitalise on the full “economic freedoms” of leaving the EU.

While he insisted that the Brexit vote was not “some great V-sign from the cliffs of Dover”, he said the benefits the single market and the customs union were “nothing like as conspicuous or irrefutable as is sometimes claimed”.

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Boris Johnson has said the benefits of the EU single market are not as ‘irrefutable’ as some claim (Dominic Lipinski/PA)

His comments were in sharp contrast with Chancellor Philip Hammond – seen as the leading Cabinet proponent of a “soft” Brexit – who has suggested Britain’s relationship with the EU may change only “very modestly” after it leaves.

Many Tory Brexiteers remain angry at the EU’s insistence that the UK must remain subject to EU law – including any new legislation passed after it had left – during the transition period, expected to last around two years.

Feelings, which were already running high, were further inflamed when it emerged the EU was proposing a so-called “punishment clause”, which could see it impose sanctions on the UK if there is any breach of the rules.

But after Bexit Secretary David Davis accused the European Commission of failing to act in “good faith”, it was reported that officials from the other 27 states had agreed to tone down the language when they publish an expanded document towards the end of February.

Former Nato secretary general Anders Fogh Rasmussen called for greater urgency in agreeing the post-Brexit security relationship between the UK and EU, calling on Mrs May to present “very concrete ideas” on Britain’s vision of the future.

Mr Rasmussen told BBC Radio 4’s Today programme: “I have urged the negotiators on both sides to start negotiations on security issues already now. I am concerned that as far as we can see, security is not on the radar screen right now.
But it’s very, very complicated.

“When it comes to trade, you have the WTO (World Trade Organisation) tariffs as a fallback. But when it comes to security, you don’t have any fallback option. That’s why you have to address these issues in due time.”

The former Danish prime minister said negotiations on a UK/EU security treaty should begin “right away”, adding: “Even the UK must realise that in today’s world, its strength is very much dependent on co-operation with other countries. Brexit
has been decided, it will happen. But I think it’s in both the UK’s and the EU’s interest to maintain strong links if the UK should maintain its strong and very appreciated role on the international scene.”

In order to continue data-sharing with the EU in the realm of security, the UK would have to continue to observe Brussels regulations, he warned.

“I would like to hear from Prime Minister May that she realises how important it is for not only the UK but also the EU to continue close co-operation,” said Mr Rasmussen.

“And also I think the Brits should realise that, while you are leaving
the EU, you will still have to comply with rules that are decided within the European Union – for instance on data protection, including the European Court of Justice.”

Former director of GCHQ Robert Hannigan (Dominic Lipinski/PA)
Former director of GCHQ Robert Hannigan said the speech should include detail (Dominic Lipinski/PA)

The former director of the Government’s GCHQ eavesdropping centre, Robert Hannigan, told BBC Radio 4’s Today programme that Mrs May should use her Munich speech to “give some detail and set out a plan”, warning that she will “disappoint” her European audience if she simply restates her wish for a special security partership.

“People now – as in every area of Brexit – want to hear some detail about what does that mean and on the really difficult issues what is the plan that is going to be put to Brussels,” he said.

He added: “One of the things we will be withdrawing from are those mechanisms that influence European policy on sanctions and other areas of common security and defence policy. The Government has said it wants to be fully part of that conversation.

“It needs now to set out, what’s the proposal for that? How are we going to interact with the EU in future on policy on defence and security?”
 
The UK was being “massively distracted by Brexit and will be for the foreseeable future”, said Mr Hannigan.

He warned that Britain’s defence industry “is likely to start a steady decline” if it loses the ability to collaborate on research and innovation with the increasingly integrated EU defence sector.
 
“Increasingly, our defence sector – which is incredibly important to us, hundreds of thousands of jobs right across the UK depend on that sector – has been collaborating with European partners, particularly on research and innovation, which is no longer really affordable for a medium-sized country,” said Mr Hannigan.
 
“To compete in the modern market and export outside of the EU – where most of our defence exports go – we need to collaborate. Will that be possible in the future?”