Winnie Madikizela-Mandela on Friday said she never granted an interview to a journalist who quoted her in a British newspaper as saying her ex-husband Nelson Mandela had "let down" the blacks.

"I did not give Naipaul an interview. It is therefore not necessary for me to respond in any detail to the contents of a fabricated interview," Madikizela-Mandela said in a statement, referring to Nadira Naipaul, the wife of acclaimed novelist V.S. Naipaul.

"I will in the coming days deal with what I see as an inexplicable attempt to undermine the unity of my family, the legacy of Nelson Mandela and the high regard with which the name Mandela is held here and across the globe," she said.

However local media said Madikizela-Mandela spoke to Naipaul but was unaware the conversation was an interview.

Her scathing comments about the internationally respected statesman were reported in the London Evening Standard this week where she was quoted as saying: "Mandela let us down. He agreed to a bad deal for the blacks."

"Economically, we are still on the outside. The economy is very much 'white'. It has a few token blacks, but so many who gave their life in the struggle have died unrewarded," the 73-year-old said in the paper.

"This name Mandela is an albatross around the necks of my family," she said.

Madikizela-Mandela who was currently in United States said it was not necessary for her to respond "in any detail to the contents of a fabricated interview."

Madikizela-Mandela said she had spoken to Nobel peace laureate Archbishop Desmond Tutu, who was also in the US, after the interview in which she was quoted as calling him a "cretin" and dismissing South Africa's much-lauded Truth and Reconciliation Commission, which he headed, as a "charade".

Madikizela-Mandela campaigned tirelessly for her husband's release during his 27-year imprisonment under white-minority apartheid rule. He was released 20 years ago.

However her image was tarnished by a series of scandals including a kidnapping and her assault conviction over the killing of a young activist, and a 2003 conviction for fraud.

She separated from Nelson Mandela in 1992, two years after his release, but she remains a popular South African figure in own her own right.