Britain's interior minister visited immigration facilities on England's southeastern coast Thursday as she grappled with an overcrowding crisis at a migrant facility and outcry over her claim that the U.K. faced an invasion of asylum-seekers.Home Secretary Suella Braverman is under heavy pressure to address potentially unlawful conditions at Manston, a converted airfield that has held some 3,500 people who made the hazardous journey across the English Channel on small boats to U.K. shores.