Meryl Streep is being trumpeted as a likely Oscar winner for her performance as Margaret Thatcher in The Iron Lady, but the film worries John Campbell, on whose biography it is based.

“Like any film of that sort, it simplifies and it dramatises her as a great individual, fighting against all these things as if it was just her on her own,” says the author, who acted as a consultant and was even given a cameo role as the manager of an ice-cream company visited by Thatcher.

“It does not credit her colleagues like Geoffrey Howe, or anybody else. The other politicians are made to look wet – she bashes them....