Commenting following Boris Johnson's address to the nation on Ukraine, Liberal Democrat Leader Ed Davey said:
"At this dark moment we must renew our commitments of international cooperation and stand with our allies against this horrendous invasion.
"For too long we in the West have been complacent about the threat which Putin poses to our allies and to the fundamental values which underpin our way of life. No more.
"We must stand with the people of Ukraine and provide them with humanitarian and military aid, while unleashing the severest of sanctions against Putin and his cronies.
"The era of Russian interference in this country must come to an end. Much of the legislation needed is ready to go - it must be brought before MPs immediately. Parliament must sit this weekend, day and night if we have to, to pass the necessary measures and impose the most punitive of sanctions upon Putin's regime."