The question is how do you control it? (Because it will not be stopped for 1000 reasons.)
The only answer is a treaty with the EU to take our fair share of refugees coming to Europe. Bring them in and process them in a controlled manner, and once processed add them to the labour force.
Under the treaty, anyone lacking the appropriate papers would be shunted back to mainland Europe the same day.
This is what I call a reasonable and pragmatic policy, but as it would not appeal to retired Lieutenant Colonels in Cheltenham, the Tories would never do this.