Theresa May is flying into the heart of a massive European storm as she visits Poland for talks with the eastern European country's new prime minister.
The visit to Warsaw comes a day after the European Commission triggered proceedings against Poland which could lead to sanctions over a contentious overhaul of its justice system.
Speaking ahead of the trip, the Prime Minister's official spokesman said Mrs May would "raise her concerns" over the changes with Polish counterpart Mateusz Morawiecki, who has been in office for less than a fortnight since the resignation of Beata Szydlo.
Mrs May is being joined at the long-scheduled Anglo-Polish Inter-Governmental Consultations by ministers including Foreign Secretary Boris Johnson, who will later fly on to Moscow for potentially the biggest diplomatic challenge of his time in office.
Mr Johnson will meet Russian counterpart Sergey Lavrov on Friday at a time when relations between Moscow and the West are at their coolest for several decades.
The European Commission action against Poland came in response to several laws enacted by the right-wing Law and Justice party to give it greater control over the justice system.
European Council president Donald Tusk, a former Polish prime minister, said the laws had "practically liquidated judicial independence in Poland", placing government authorities "above the law".
The so-called Article 7 process could ultimately lead to sanctions including withdrawal of voting rights in the European Council, although Hungary has indicated it would wield its veto to prevent this.
Asked whether the visit so soon after the Commission's censure amounted to an endorsement of the Polish administration, Mrs May's official spokesman said: "We place great importance on respect for the rule of law and we expect all our partners to abide by international norms and standards.
"The Prime Minister will raise her concerns with the (Polish) prime minister when they meet. We hope that Poland and the Commission can resolve this through discussion."
Meanwhile, the Prime Minister is expected to announce a new joint UK-Poland Treaty on Defence and Security Co-operation, calling it a "powerful symbol of our continued close co-operation".
Speaking ahead of the summit, she said: "Poland matters greatly to the UK. Our partnership is broad, vibrant and diverse and we both share a steadfast commitment to Europe's security and defence.
"I am determined that Brexit will not weaken our relationship with Poland. Rather, it will serve as a catalyst to strengthen it."
Mr Johnson's visit to Russia is the first by a British foreign secretary for more than five years and is set to see a series of frosty exchanges over issues including Ukraine, Syria and allegations of Russian interference in Western democracy.
Moscow has sought to characterise the visit as a move back towards "business as usual" after years in which relations with the West have been in the deep-freeze following its support for separatists in Ukraine and the 2014 annexation of Crimea.
But Mrs May left no doubt that she is not ready for a thaw when she used last month's high-profile Mansion House foreign affairs speech to accuse President Vladimir Putin of using cyber-espionage and disruption to "sow discord in the West" and warned the Kremlin: "We know what you are doing. And you will not succeed."
The UK was a firm supporter of the European Union's decision last week to roll over sanctions imposed on Russia over its interference in Ukraine and continues to insist that Moscow must live up to the terms of the Minsk Agreement which required it to cease support for armed separatists.
Mr Johnson is expected to detail fundamental disagreements with Russia's positions on a string of issues.
He will seek a clear and frank exchange of views on terms which are appropriate for two members of the UN Security Council, but will not extend the hand of friendship to Moscow.
High on the agenda for his talks will be efforts to revive the political process towards a settlement in Syria, where Russian firepower has helped President Bashar Assad defeat militants of the Islamic State terror group.
The two men are also expected to discuss the tensions over North Korea's nuclear missile programme, as well as Iran, Yemen and broader concerns over European security.
Mr Johnson is also expected to seek meetings with human rights activists, and he is likely to have discussions about the security of England football fans planning to visit Russia for the World Cup next summer.
Mr Putin is facing presidential elections in March, and while there is little doubt he will emerge victorious, the prospect that the 65-year-old might be entering his final six-year term in the Kremlin has given rise to speculation over the eventual handover of power to a new leader.