Personally I would give all those who wished to go a one way ticket, on the condition that they all handed in their British passports at the check-in. Unfortunately, as Tonks says (Hi Tonks How is sunny St Andrews?) they would only appear back at the Chunnel entrance in a few weeks time asking to get back in!!
Interesting to note that all the yooof of certain 'British' towns and cities that a few weeks ago were saying that they were as British as anyone else because they were born here don't seem to be proclaiming it as loudly as before. Now they all seem to be muslims!! Is that a state? Or just a state of mind!