It is true some suggested that curtailing unstoppable EU immigration would likely pull in immigration from elsewhere, but we all know that would not be great in numbers.
Surely there is no one in the country unaware that the main reason to curb immigration is that we are already overfull, blighted by urban sprawl, and want to get the unemployed here in work not suck in more citizens from elsewhere. Only where we are desperate and haven't sorted the system to get the unemployed in work and contributing would immigrant labour be reluctantly considered.
I can't see how anyone can say they were mislead, if they did they'd surely die of embarrassment having confessed to utter foolishness.