How immigration has caused problem after problem for Tory prime ministers

Boris Johnson has made big promises but time is running out to implement a plan, writes Lizzy Buchan

Johnson’s promises have been dismissed by independent advisers (Getty)

Immigration policy has proved a double-edged sword for the Conservatives in recent years.

Ramping up rhetoric against migrants has won the Tories votes at times but at other points it has alienated swathes of the public, annoyed business leaders and caused the party to tie itself in knots.

David Cameron promised to keep net migration to the “tens of thousands” during the coalition years, partly toughening his rhetoric to neutralise the advance of Nigel Farage’s Ukip.