Does Italy have the right idea?

[JBR]

A lot do though. Italy is a handy destination for those crossing the Med from North Africa

Yes, of course they almost all come into Europe from the south.  They are highly unlikely to come via Russia!  I can believe that the largest entry point is Italy, but on the other hand why so few via Spain?
Is there something about Spain which puts them off?

We could very easily put them off coming to Britain.  All we need to do is stop giving them everything which we do.  I am sure that the vast majority of them bring nothing of any worth to us; they are take, take, take.
It would be very easy to turn around all the boats in the Channel.  It would also be perfectly possible to search every single lorry (or other vehicle for that matter) before they are allowed to board a ferry to the UK.  Yes, it would necessarily slow down the transport of goods to this island, but that would be to our distinct benefit.