No I can't, just like all the racist, xenophobe screamers can't back up theirs!!
Actually there is data that immigration was the most coherent reason of voting leave. Ironically especially in parts of the country with small immigration
https://www.theguardian.com/politic...migration-fears-were-paradoxical-but-decisiveBobby Duffy, of Ipsos Mori, whose surveys found that two weeks into the campaign immigration had replaced the economy as the single most important factor driving the leave vote, said polling showed that the actual direct impact on peoples local areas and lives is much less widespread than the general concern.
That doesnt mean the concerns arent real we can be legitimately worried about how immigration is changing our country and putting pressure on other parts of society and services like the NHS. But it is still remarkable that the single most important factor driving the leave vote actually only has a direct negative impact on one in five of the population.
When that general concern was confirmed by the national net migration figure of 333,000, regardless of the impact of new migrants on their own lives it gave leave campaigners lift-off.