Why did Mansfield agree to act for Fayed?

With the Diana inquest finally over, one question remains unanswered: why did the radical QC Michael Mansfield (left), who made his brilliant reputation by taking on miscarriages of justice and defending the indefensible, agree to represent Mohamed Fayed (right) whose conspiracy theories about the Royal Family and the Secret Service were, in the words of the coroner, "so demonstrably without foundation"?

Mansfield is the man who won acquittals for, among others, the Birmingham Six and the Newham Seven; who helped clear the names of dozens of picketing miners after the Battle of Orgreave; who represented the families of Stephen Lawrence and Jean Charles de Menezes; who, in short, has taken the side of the underdog. So why did he take the case of the Harrods owner, some of whose allegations were so preposterous that Mansfield had to distance himself from them in the High Court? Here are four possible answers:

One, the money. According to the Lawyer magazine, Mansfield has been working for Fayed at an hourly rate of £575. Over the past six months and beyond, that will have added up to hundreds of thousands of pounds.

Two, the stage. Mansfield loves attention, according to his fellow QCs, and the Diana inquest guaranteed that. He will probably win the title of the lawyer most mentioned in the media this year in the annual survey by legal publishers Sweet & Maxwell. He was pushed into second place last year by Cherie Blair.

Three, the cab rank rule. It is the Bar convention that a barrister, like a London taxi, is available to anyone. Who would defend people like Ian Huntley - the murderer of the Soham girls - if barristers could pick and choose their clients?

Four, the underdog theory. Mansfield enjoys representing the put-upon and oppressed - and who could be more of an underdog than the son of an Egyptian school teacher who believes his son has been murdered by the establishment?

As Tim Willis wrote for The First Post in his 'tribute' to the great Mansfield two months ago, "Armed only with the slingshot of huge fees, he has determined that one immigrant shopkeeper's voice will be heard."