NEW: Former Ukrainian MP denies Russia plot

A former MP in Ukraine has told this programme he could sue the British Foreign Office after it said the Kremlin was plotting to install him as a pro-Moscow leader in Ukraine.

Yevhen Murayev, who was named in an overnight briefing from the UK government, has denied any such plan exists.

But today a British minister insisted there is still a “significant risk” that Russia could invade Ukraine.