A mix of stories make up the front of Sunday’s newspapers. The Observer’s lead focuses on the issue of defective concrete which has dominated the news since schools began to return at the end of last week. The paper has an exclusive interview with a “senior civil service whistleblower” who has told the paper that Tory ministers and their advisers were “dangerously complacent” about aerated concrete, and were “more concerned with saving money than improving safety”. The front of the paper also trails an interview with Channel 4 News presenter Krishnan Guru-Murthy, who is set to compete in Strictly Come Dancing.