Why fight it? Why not accept that the democratically elected government just do not want you. Act accordingly and leave - when you stop banging your head against the brick wall life feels a whole lot better.
Eventually it will dawn on them that they have no power any more and maybe some small dissident group will kick their backsides out of Whitehall before the next opportunity to con the British public at an election. It would be wonderful to watch them trying to cobble together a defensive force from the few remaining backside lickers in MOD.