Image copyright AFP Image caption Lessing won the Nobel Prize for Literature in 2007

Nobel Prize-winning author Doris Lessing was spied on by security services for more than 20 years over suspicions of her communist sympathies, newly declassified records show.

Lessing's movements were documented during her younger years by MI5 both in her homeland in Africa and in England.

It was her anti-racism stance as well and her Communist Party membership that worried MI5.

Lessing, who died in 2013 aged 94, won the Nobel Prize for Literature in 2007.

Her books include The Golden Notebook, The Sweetest Dream and The Grass is Singing, as well a number of short story collections.

She was born in Kermanshah, in western Iran, where her British father was a clerk with the Imperial Bank of Persia.

In 1925 the family moved to Southern Rhodesia, now Zimbabwe - where she met and married her second husband German Communist Gottfried Lessing in 1945. They divorced in 1949.

The security services trailed her between 1943 and 1964.

Image copyright PA Image caption The MI5 file contained Lessing's Communist Party registration document

It was during her time in Africa that she roused the attentions of security services, who viewed her membership of several left-leaning groups with suspicion, including the Rhodesian Friends of the Soviet Union.

She also ran the Salisbury Left Club in Southern Rhodesia, a club "patronised by persons with foreign accents", the records show.

It said: "The general tone of this club is reported to be very left, and it is stated that most topics of discussion there usually end up in anti-British, anti-capitalist and anti-imperialist vapourings."

Lessing was particularly vocal about the poor treatment of black Africans.

"Her communist sympathies have been fanned almost to the point of fanaticism owing to her upbringing in Rhodesia, which has brought out in her a deep hatred of the colour bar," a note in her MI5 file reveals.

"Colonial exploitation is her pet theme and she has now nearly become... irresponsible in her statements... saying that everything black is wonderful and that all men and all things white are vicious."

Image copyright PA Image caption Lessing moved to Britain in 1949

Scotland Yard's Special Branch also compiled a file on her in 1950, and authorisation was given to intercept post sent to an address where she was staying in Berlin.

Also in the file was a note compiled by Metropolitan Police's Special Branch in 1965 about her activities in London.

"Her flat is frequently visited by persons of various nationality, including Americans, Indians, Chinese and Negroes," the report said.

"Some of the visitors seem to stay at the flat for days at a time and some of the visits are made by apparently unmarried couples. It is possible that the flat is being used for immoral practices."

The same year, Lessing left the Communist Party over the Soviet Union's involvement in Hungary.

Later, speaking about her Communist Party affiliations, Lessing said: "I can't understand why I was so gullible."