It is impossible for the state to provide free education, struggle veteran Winnie Madikizela-Mandela said on Thursday.

She was speaking from her former home on Vilakazi Street in Orlando, Soweto, where she was giving former Manchester United legend Rio Ferdinand a tour.

"Free education is difficult to attain because of problems from those times. How did we think we were going to get money to fund education from the onset?" she asked.

She cited the structure of South African society as being problematic, referring to it as a strangely defined society.

Madikizela-Mandela also said it was impossible to deliver on some of the promises made in the Freedom Charter.

"In 1994, we realised the free education we promised was not going to be easy," she said, adding that due to a lack of experience, leaders had not acted on undertakings of the Freedom Charter.

Students have been protesting throughout the week, following an announcement by Higher Education and Training Minister Blade Nzimade in which he recommended an increase, to be capped at 8%, which the government would subsidise for the poor and the "missing middle".

Madikizela-Mandela said it might be time to revisit the Freedom Charter. She further explained that the demand for free quality education by students across the country put the state in a difficult position.

"It seems a very, very difficult problem. How do you differentiate the students from southern suburbs, whose parents can afford, from those who come from the shacks."