LONDON (AFP) - Media tycoon Rupert Murdoch on Wednesday paid tribute to former British prime minister Margaret Thatcher, crediting her with giving him the strength to face down print unions in the 1980s.

Writing in the Times, one of his News International titles, Mr Murdoch called Mrs Thatcher, who died on Monday aged 87, "the woman who gave us back our backbone" and "undoubtedly one of the most important figures in the 20th century.

"I found her attitude an inspiration in my business life - and never more so than when faced with the recalcitrance of the print unions in the 1980s," he wrote.

Printers were angered by Mr Murdoch's decision to shift production of his newspapers to a hi-tech, less labour intensive, site in east London in 1986.

The controversial businessman said Mrs Thatcher had swept away Britain's post-war "dependency state", which he claimed had "killed off aspiration.

"Mrs Thatcher understood that risk was a vital ingredient in a free enterprise society," he wrote.

"She held firm in pursuit of her belief in aspiration, in the power of individual people to make the most of their talents to improve their own lives and those of their families and of society.

"Thanks to her I have experienced in Britain many of my defining moments as a businessman, a Britain that is far more successful as a result of her brave leadership," he added.