The treaty is part of Starmer’s efforts to deepen cooperation with the European Union, which the UK voted to leave in 2016 following a divisive referendum campaign, Euronews reported.

The document will cover a wide range of issues, including border security, the fight against organised crime, the strengthening of collective defence and deeper cooperation with the European Union. The British prime minister’s office said the countries also intend to jointly develop new air defence systems, including the launch of joint production of medium-range anti-aircraft missiles.

Ahead of his visit to London, Polish Prime Minister Donald Tusk stressed that the deepening of the defence alliance between London and Warsaw is aimed at countering a potential threat from Russia.

Tusk also confirmed that the purpose of concluding the bilateral agreement is to secure faster mutual defence guarantees in the event of an attack, despite the existence of the collective defence mechanism within NATO.