changing to sane immigration policies
will lead to civil war
it is already too late
it is possible to avoid a complete takeover
but not without a civil war
The only peaceful way to save Britain:
Step 1: Close the country down. Don’t let even one more illegal get in.
Step 2: Pay each illegal already there whatever it takes to get them to leave.
Both steps require more than a little courage.
Neither step stands even the remotest chance of happening. So as you noted, it’s either civil war or a complete takeover. I suppose the blokes in the barracks will have the final vote on that.