One of the government’s key contractors has launched an investigation into allegations of racism, antisemitism, Islamophobia and hate speech among staff working in immigration removal centres, the Guardian has learned.Whistleblowers from the company, Mitie, have alleged that some staff members working in immigration removal centres and deporting migrants have made offensive comments at work and in social media posts.A dossier of examples, seen by the Guardian, has been sent to Mitie bosses, who said they were investigating.The Home Office said the allegations were a matter for Mitie.Allegations in the dossier include Islamophobic comments made at work. One staff member allegedly...