We will have to eventually welcome back our European neighbours, to entice them back into the fields, factories, cleaning jobs, etc. or look further afield, to the commonwealth maybe, and encourage more people to come from India, Pakistan, Caribbean etc.
A friend who works in the UK for a Chinese company, says Taiwan workers are great - have an Chinese work ethic while also having a western outlook thanks to years of American influence. If China gets its way (it says it wants to take back control of Taiwan, no matter the cost) then the world might have a lot of Taiwanese refugees looking for a new home and job.
But, we have boatloads of people arriving, all eager to start a new life in a liberal society, so rather than persecute them maybe we should just provide them asylum, sanctuary, jobs, and let them help us work through the Brexit mess.