A new exhibition in London will show pictures drawn by Nelson Mandela depicting his time in prison.

The sketches, drawn using charcoal and crayon, form part of the Black and White Exhibition which opens at the Belgravia Gallery, central London, from 20 September.

Mr Mandela, who has become a keen amateur artist, is hoping the display will help to raise money for his charity, the Children's Fund, which helps orphaned children and those with the HIV virus in South Africa.

The exhibition includes views from the prison in Robben Island, off Cape Town, where he spent most of his 26-year sentence.

Mr Mandela returned to the island to draw the sketches.

"I think there will be huge interest in the exhibition," said a spokeswoman for the Belgravia Gallery.

Lithographs of the sketches will be on sale, with prices starting at �1,700, to raise money for the Children's Fund.

Mandela, 84, was sentenced to life in prison in 1964 for plotting to overthrow the state, and spent most of his sentence on Robben Island doing hard labour in a lime quarry.

He was released from prison in 1990, was awarded the Nobel Peace Prize in 1993 and became President of South Africa the following year.

In 2001 he was diagnosed with prostate cancer, but was given the all-clear in February this year following a course of radiotherapy.

Other highlights of the Black and White exhibition will include signed lithographs from Picasso, photographs from Sebastian Hunter, pastels by Charlie Mackesy and charcoal drawings by Trudy Good.

The gallery is well known for exhibiting the works of contemporary artists, and has raised over �4m for the Prince Of Wales Charitable Foundation.