Pakistan, Sept. 11 -- A coach carrying Pakistan's Under-19 cricket team pulled into a Portsmouth hotel this week and, because the passengers appeared to be foreign, word soon spread online that asylum seekers had been brought into the city. Masked protesters gathered outside. The error may have been corrected, but the circumstances in which it was made deserve more attention than the embarrassment of having identified the wrong hotel guests.

Britain is dealing with a combustible argument over irregular migration and border control. Only two days earlier, 625 people had reached the country in eight small boats, followed by another 143 the next day, according to provisional Home Office figures. Hundreds of anti-immigration demonstrators ha...