Hain's book on his hero Mandela

Peter Hain meeting Nelson Mandela in 2000

Former cabinet minister Peter Hain is writing a biography of Nelson Mandela.

The one-time Wales and Work and Pensions Secretary has secured an advance of about £5,000.

"There are lots of books about him but they are all long and learned," said Mr Hain. "I have been asked to write a shorter, popular book."

Mr Hain left his cabinet posts in January and is waiting to hear whether he will face charges for the late declaration of campaign donations.

The details of the biography are included in the latest register of MPs' outside interests.

Mr Hain said he had been asked to write a short and popular book on his friend and hero, and hopes it will be published next year.

"I knew him through my actions against apartheid. I also worked with him as Africa minister," he said.

The Neath MP ran for the deputy leadership of the Labour party last year but came fifth out of six candidates.

All those taking part should have told the Electoral Commission about any donations towards the campaign.

Peter Hain during an anti-apartheid protest in London in 1973

Mr Hain has admitted that although he declared £77,000 on time, a further £5,000 was not declared until November - and in January he admitted that a further £103,000 should have been reported.

Police have handed over evidence relating to the donations to the Crown Prosecution Service.

The register of interests lists the earnings of Mr Hain's other former ministerial colleagues.

John Prescott has earned some £140,000 from his autobiography and from speeches since he stepped down as deputy prime minister a year ago.

But the register shows other big earners among MPs.

Shadow foreign secretary, and former Conservative Welsh Secretary William Hague earns up to £25,000 a time from speeches.

He has also written biographies of William Wilberforce and William Pitt the Younger.

.