Organizers of the funeral of Baroness Thatcher are said to be increasingly concerned that Sir Mark Thatcher might lose his way on the drive to St Paul's Cathedral.
His mother launched a major international rescue mission when he got lost for six days in the Saharan desert during the 1982 Paris-Dakar rally.
'We are keeping a close watch on Sir Mark,' said one of the funeral organizers. 'We don't want a repeat of 1982 and the funeral cortège going missing somewhere in Central London.'
But David Cameron - whom Baroness Thatcher is said to have been contemptuous - is said to be more concerned over what Sir Mark may be planning immediately after the funeral.
In 2005 he was given a four-year suspended sentence in South Africa after involvement in an attempt to overthrow the government of Equatorial Guinea.