Iran's fatwa on Salman Rushdie has never been formally withdrawn (File Photo)

The latest biography of Margaret Thatcher sheds new light on the role played by the former British Prime Minister in protecting Mumbai-born author Salman Rushdie after a fatwa was issued by Iran's Ayatollah Khomeini in 1989 over the release of his controversial book 'The Satanic Verses''.

Charles Moore's third volume in his series of 'Margaret Thatcher: The Authorised Biography'', which is released on Thursday, reveals some behind-the-scenes activities as the British government sought to protect the Booker Prize-winning author's life in the UK.

"Mrs Thatcher was certainly sympathetic to Rushdie's personal plight, but it was principle, not tenderness, which actuated her in this case - the rule of law and the basic freedoms of British citizens, whatever their beliefs," notes Moore, in extracts from his book in 'The Daily Telegraph''.

"Rushdie had previously described the British police as the colonising army, those regiments of occupation and control. Now he sought - and received - their full-time protection at taxpayer's expense. Rather to the astonishment of everybody, we didn't hesitate to protect him, recalled William Waldegrave, then a Foreign Office minister," Moore adds.

The author also recalls that while Margaret Thatcher, a Conservative Party Prime Minister from 1979 to 1990, did not "warm to Rushdie himself" due to his Left-wing leanings, she agreed with her advisors and Cabinet ministers that the fatwa was an attack on the fundamental freedoms for which British society stands.

Downing Street learnt that Tehran was seeking to recruit "some suitable Nigerian to carry out the execution" and similar recruitment drives were reported in other countries.

"Whether or not we have any sympathy with Rushdie's views is not the point. We must react strongly to any state murder-hunt made against one of our citizens," Thatcher is quoted as saying in one of her notes on the matter.

To keep him safe, the British police is recorded to have moved him between 57 different locations in five months at the height of the death threat.

Moore records that when Khomeini died in June 1989, offers came from potential intermediaries including Mohamed Iqbal, a relation of Akbar Hashemi Rafsanjani, the "moderate" Iranian who became President in August that year.

Famous British romance novelist Barbara Cartland emerged as an unlikely player in the mediation as a friend of Iqbal.

"But very little progress was made and Rushdie remained under constant protection," notes the author, whose volumes on one of Britain's most famous Prime Ministers are based on unrestricted access to Thatcher's papers, unpublished interviews with her and all her key colleagues.

While Iran's fatwa on Rushdie has never been formally withdrawn, the author came out of hiding around 1998 after a commitment to the British government from the Iranian government of the time.