In keeping with the old adage that it pays to be wary of a wealthy man whose fortune is difficult to fathom, multimillionaire Sir Mark Thatcher raises the hackles of some of his mother's closest followers, and her political enemies.
As prime minister, Mrs Thatcher preached the value of self-sufficiency, the virtue of individuals standing on their own two feet. Yet the apron strings were never cut with the son she adored.
Instead "Scratcher" was accused of ruthlessly exploiting his famous surname and access to power, inviting business associates to ring him in Downing Street and dangling the prospect of meetings with his mother, to set him on the road to riches.
A fixer, wheeler-dealer, middle-man and one-time self-styled playboy, Sir Mark (51) - who inherited his baronetcy last year when Sir Denis died aged 88 - can be in turn cocky, aloof and arrogant. His wealth is estimated at up to £60 million, a figure he earlier this month, dismissed as "widely off the mark", without revealing whether it was too high or too low.
What is undoubtedly true is that he has done particularly well financially for someone who left fee-paying Harrow school (where his nickname was "Thickie Mork") with three O-levels and mediocre A-levels, and who subsequently failed his accountancy examinations three times.
Mark Thatcher was born on August 15th, 1953. He and his twin sister Carol, a journalist, were delivered by Caesarean section while their father watched a Test match at the Oval cricket ground.
Baroness Thatcher, to the astonishment of many of her admirers, saw no fault in Mark, but did not have the same feelings towards Carol.
Mark Thatcher first came to public prominence in 1982 when he was lost in the Sahara desert for six days during the Paris to Dakar rally, his mother weeping in public and Sir Denis flying to north Africa to join the search party.
A business deal two years later was to cause his mother almost as much grief and prompt a barrage of questions about whether the prime minister's son was using Downing Street to unlock doors.
The day after Lady Thatcher landed in Oman in 1981 to clinch a £300 million university construction deal for Cementation, a Trafalgar House subsidiary, the young Thatcher arrived in the desert kingdom and claims were publicly aired that he pocketed payments as an intermediary in the contract.
A similar charge of a conflict of interests was played out after his mother signed the al-Yamamah arms deal with Saudi Arabia and he was alleged, based on transcripts of telephone conversations between Saudi princes and agents, to have enjoyed £12 million in commissions.
Six years ago, after settling in South Africa in 1995, Mark Thatcher caught the attention of the authorities over allegations of unofficial small loans to police officers, military personnel and civil servants, who were charged 20 per cent interest and were pursued by debt collections if they defaulted.