The latest gambit by the alliance of MPs around Sir Oliver Letwin looks like a real problem for the government whips, as they prepare for Saturday's critical vote on the new-look Brexit deal.

The government's top Brexit official, Oliver Robbins, has left the Department for Exiting the European Union and is moving to the Cabinet Office to work more directly for the prime minister.

Former Brexit negotiator Sir Oliver Robbins has been appointed as the top civil servant at the Foreign Office. He will take over from Sir Philip Barton, who became permanent secretary of the ...