British Prime Minister Boris Johnson on Thursday defended his controversial deal to expel migrants to Rwanda, telling critics to “keep an open mind”. On the first day of a trip to Kigali – which is hosting a Commonwealth summit this week – he also heaped praise on Rwandan President Paul Kagame and the achievements of his tiny African country, despite widespread concerns about its human rights record. The London-Kigali scheme, which involves Britain deporting asylum seekers thousands of miles away to Rwanda, has provoked a storm of outrage. But Johnson told reporters: “The critics need to keep …