Theresa May is preparing for a key Brexit-focused meeting with newly elected German Chancellor Angela Merkel.
The two leaders will meet on the sidelines of a European Union summit in the Estonian capital Tallinn.
It is the first face-to-face meeting between Mrs May and the German Chancellor, a key leader in the EU hierarchy, since Mrs May’s speech in Florence in which she outlined her vision for Brexit.
Angela Merkel was re-elected as the German leader last weekend but with a weakened political grip. She now has many months of coalition building before she can form a government in Germany.
The EU summit, held in Estonia because it holds the current EU rotating presidency, is billed as a “digital summit”.
It is designed to focus attention on innovation, research and investment to help foster a digital revolution.
However, from a British perspective, Brexit is the focus.
On her arrival, the Prime Minister addressed some of the 800 British troops serving with the NATO mission in Estonia, where she insisted the UK will remain “unconditionally committed to maintaining Europe’s security” after Brexit.
The deployment was made in April in order to help provide a deterrence against what NATO and western Governments perceive as increased Russian assertiveness.
Mrs May declared they stood ready to defend European nations from any possible threat from Russia, a country she accused of “deliberately” violating the “rules-based international order that we have worked so hard to create”.
The Prime Minister said: “Russia’s continued aggression represents a threat to our friends here in Estonia, as well as in Latvia, Lithuania and Poland, and our response must be clear and unequivocal.
“That is why this mission that you are carrying out is so important.
“By stepping up NATO’s deterrence and defence posture, you are showing that we are equipped to respond to any threat we face, you are showing that we are ready to do so.”
Insisting the UK “will always stand with our allies”, the Prime Minister added: “While we are leaving the EU, as I have said many times, we are not leaving Europe.
“So the UK is unconditionally committed to maintaining Europe’s security.
“We will continue to offer aid and assistance to EU member states that are the victim of armed aggression, terrorism and natural or man-made disasters.”
The Brexit/security question has come under significant scrutiny over the past few months with some accusing Mrs May of using defence and security as a bargaining chip in the Brexit negotiations.
In her letter triggering Article 50 – the UK’s formal intention to leave the EU – Mrs May seemed explicit that security co-operation was conditional on a deal.
In the March letter she wrote: “If … we leave the European Union without an agreement, the default position is that we would have to trade on World Trade Organisation terms.
“In security terms, a failure to reach agreement would mean our co-operation in the fight against crime and terrorism would be weakened.”
Since then, the British tone has softened.
Last week in Florence, she said: “The United Kingdom is unconditionally committed to maintaining Europe’s security.
“And the UK will continue to offer aid and assistance to EU member states that are the victims of armed aggression, terrorism and natural or man-made disasters.”
This latest intervention, combined with a visit to see the British troops based in Estonia, appears to be an attempt to reassure her fellow leaders that British security support is unconditional.
The 28 EU leaders convened for a working dinner hosted by EU Council President Donald Tusk prior to the summit.
Mrs May sat with Portuguese Prime Minister Antonio Costa on her left and Polish Prime Minister Beata Szydlo on her right.
Brexit is bound to have been discussed, and with PM Szydlo two of the three divorce issues – citizen’s rights and the financial settlement – are key issues.
Poland is concerned about the fate of many hundreds of thousands of its citizens who live in the UK and who are currently unsure about their future.
On the financial settlement, Poland is one of a number of Eastern European countries who stand to lose out if Britain leaves a hole in the EU budget.
On Wednesday the fourth round of negotiations concluded in Brussels with both sides claiming some progress.
“We have had a constructive week yes but we are not yet there in terms of achieving sufficient progress, more work is needed over the coming weeks and coming months,” EU chief Brexit negotiator Michel Barnier said.
“The only way to reach sufficient progress is that all commitments undertaken at 28 [member countries] are honoured at 28,” he said, referring to what he believes is Britain’s responsibility to pay a financial settlement.
The UK Brexit Secretary, David Davis, said: “I believe that thanks to the constructive and determined manner with which both sides have conducted…