Troubles deepened for Lady Thatcher's disgraced son last night when a self-confessed coup plotter surfaced to accuse him of direct involvement in the attempt to overthrow the regime in Equatorial Guinea. Crause Steyl, the mercenary pilot who was to have been the star witness against Mark Thatcher had his trial in South Africa gone ahead, told Channel 4 News that Sir Mark's role had been kept secret, because "his mother was the previous prime minister of England". Mr Steyl described meeting Sir Mark to select a helicopter on which a gun could be mounted. He also alleged that the Spanish...