Brexit will strengthen not weaken the UK’s ties with Poland, Theresa May is to insist on a visit to Warsaw – where she will announce plans for enhanced defence and security co-operation.
Poland will still “matter greatly” to the UK after it leaves the EU, she will say, citing shared history and values.
A proposed new defence treaty will be a “powerful symbol” of co-operation, the PM will tell her Polish counterpart.
The UK will also back an initiative to blunt Russian propaganda in the region.
The treaty will be only the second bilateral defence agreement the UK has with a European ally, after France.
It will provide a framework for enhanced co-operation in training, information sharing, defence procurement and joint exercises between the Nato partners.
The proposed relationship comes after Mrs May sacked one of her closest allies, First Secretary of State Damian Green, after he made “misleading” statements about what he knew about computer pornography claims.
At a bilateral summit in the Polish capital, Warsaw, Mrs May will vow that after the UK’s departure from the EU in March 2019, the “deep ties of friendship” between the countries will continue to flourish.
“Poland matters greatly to the UK,” Mrs May will say. “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.”
Her visit comes hours after the EU announced disciplinary measures against Poland, accusing the country of undermining the independence of its judges.
Downing Street said Mrs May would raise her concerns with the Polish prime minister, Mateusz Morawiecki.
She will announce that the UK is to provide £5m of funding to a joint UK-Polish plan to counter Russian misinformation in the region.
Part of the money will go towards supporting Belsat, a “free and frank” Polish-funded TV channel broadcasting in Belarus, one of Russia’s closest allies in the region.
Last month, Mrs May said Moscow was seeking to “sow discord” in the West by meddling in elections and mounting cyber attacks against critical infrastructure.
The PM recently wrote to the 980,000 Poles in the UK urging them to stay in the country after Brexit, reassuring them that the process of applying for settled status will be quick and inexpensive.
On her visit to Warsaw, Mrs May will be accompanied by senior members of the cabinet, including Foreign Secretary Boris Johnson, Chancellor Philip Hammond and Defence Secretary Gavin Williamson.