"May’s authoritarian streak was personified by a deeply illiberal immigration policy. She championed capping net migration with a crude target and creating a “really hostile environment” for illegal immigrants, replete with “Go Home” vans deployed in highly concentrated ethnic minority neighborhoods. As home secretary, she oversaw the Windrush scandal, which resulted in legal migrants from the 1970s denied rights and in some cases even deported wrongfully.
Johnson’s instincts, in contrast, are liberal and permissive. He’s an optimist, pro-free trade and pro-immigration. He even actively championed the idea of an amnesty for illegal immigrants during the Brexit referendum campaign. Today he wants a shift to an Australian-style points-based immigration system, which former May staffers oppose."