The Lords Standards Commissioner has begun a formal inquiry into Baroness Warsi's expenses claims.
Paul Kernaghan, a former police chief, said he decided to investigate after being asked by the cabinet minister to look into the claims. The Tory peer, 41, faces allegations that she claimed accommodation expenses while staying at a friend's house rent-free. Labour had demanded a criminal inquiry into her expenses. But Scotland Yard chose not to investigate and passed the matter back to the House of Lords.
The Conservative co-chairman has insisted she made "appropriate payments" to her friend Naweed Khan, a Tory official who is now one of her aides, for nights she stayed at a property in Acton, west London.