Let's imagine for a moment that the national objective is to mainta or increase immigration. Here's how to do it.
1. Have an active foreign policy - in particular pursue military interventions which destabilise formerly sovereign nationstates.
2. Build relationships as best you can with the locals - using interpreters and speaking your own language as much as possible
3. Encourage the building of technological and travel infrastructures that allow the local population to check your integrity using your own national media via radio, satellite TV and online (hasn't the BBC done well as have so many British media brands?)
4. Promote democracy and materialism using varied content much sourced from US TV networks
5. Then stand back and watch as people whose economies have been wrecked try to migrate to the motherland to use their newfound English.
At this stage don't start sending alarmist messages to the home front suggesting we should close the borders and protect ourselves from being over run. Its far too late. By this time anyway the immigration authorities will be overwhelmed with processing asylum seekers whose claims take years to verify. They haven't the capacity to deal with anyone else.
If by chance you do want to reduce the flow of immigrants. Then consider that British hegemony is the primary driver of these population flows and the sooner we stop sending expeditionary forces (sorry peacekeepers) to various parts of the world the easier it will be to limit the flow of those who come to these shores because we have successfully promoted our way of life through military and media strenth.
Afghan refugee numbers entering Europe are up this year by 87%. Its time we started looking at causes and consequences.