After failing to boost Russia's fertility rate via pro-natalist policies and to extend life expectancies, Putin "seems to have concluded that the only way to achieve a sizable increase in his population is by annexing and subordinating ethnically and culturally related neighbors, by force if necessary."

The PM will meet troops from the UK-led Nato battlegroup in Estonia as he warns Russia is the "most acute threat" the UK faces

Here is the situation on Sunday, December 15: Russia has begun using North Korean troops in significant numbers for the first time to conduct assaults on Ukrainian forces battling to hold an enclave in the country’s Kursk region, President Volodymyr Zelenskyy said.