Grant Shapps, the Transport Secretary, also wrote to all UK ports asking them to ban any Russian flagged, registered, owned, controlled, chartered or operated vessels in advance of laws enforcing it.

Keir Starmer, the Labour leader, urged ministers to scrap the National Insurance rise because of the knock-on cost of living effect of sanctions.

Eight former Cabinet ministers including Sir Robert Buckland, Jeremy Hunt, Damian Green and Matt Hancock were among the 38 Tory MPs to put their names to a letter calling for a “flexible and pragmatic approach” to allow Ukrainians to seek temporary refuge in the UK.

The MPs said: “It is clear that this is not another migration crisis – this is a crisis of war. This should not be business as usual, we need sincere and immediate support for the Ukrainian people. The United Kingdom cannot flag or fail. Our message must be clear: Ukrainian victims of war seeking refuge are welcome.

Opposition figures criticised Ms Patel’s “chaotic” response to the crisis. Ms Cooper said: “The Home Secretary has just said she is announcing a bespoke humanitarian route, but it’s extremely unclear from what she’s said what the details actually are or who it will apply to.”

Alistair Carmichael, the Liberal Democrat home affairs spokesman, said: “Ukrainians are fleeing for their lives. They deserve far better than just more spin and confusion from our Government. The Home Secretary should come back to Parliament urgently to announce a full refugee scheme to resettle Ukrainians in the UK.”

Enver Solomon, the chief executive of the Refugee Council, said: “I feel the Government is being heartless and mean-spirited and should be going further and rapidly putting in place humanitarian visas so people have a safe route to get here to apply for asylum.”