This is a short one. From 'Revealed: Immigrants swell popoulations of British towns by 10pc' we see where people who signed up with the Worker Registration Scheme went in the country.
It doesn't take into account how many left. MigrationWatch themselves estimated that around 50% of adults have gone. The real figure could be more than that, could be less, but a significant number of workers - especially in the Eastern regions where the work they'll be doing will be seasonal - will have returned to their country of origin. So the paper's claim that the amount the population has risen is likely to be higher - probably not true.
Plus, only one town has had its population expanded by anything close to 10% - Boston, with 9.4%. The next highest is Westminster with 6.2%, and after that come Northampton at 5.1%, South Holland with 4.8% and Peterborough with 4.2%. The other 55 areas have less than 4%, and only 16 have anything above 2%.
So we have the sixty highest level alleged increase towns in the country, not a single one of them actually has an alleged rise of 10%, 95% of them have less than half that, nearly three quarters have an alleged rise of less than 2%, but the headline still says British towns (plural) have rises of 10%.