Jane Clark, wife of the former defence minister, accused Valerie Harkess, 57, and her daughter Josephine, 34, of demanding pounds 100,000 to keep allegations that Mr Clark seduced them and Josephine's sister, Alison, out of the newspapers.
Mrs Harkess and her 64- year-old husband, James, a former deputy circuit judge, denounced the blackmail allegation as 'an absolute lie'. Her daughter accused Mr Clark of betraying her family's trust by indecently exposing himself to her and Alison when they were 13 and 15.
The Harkess family made their claims on Sky Television just hours after flying in to Heathrow from their home in South Africa.
Mr Harkess, who claims he only recently found out about a 14-year affair between Mr Clark and his wife, and additional liaisons with his step- daughters, said he would still like to 'horsewhip' Mr Clark, who had betrayed his trust as a friend of the family.
Last night at his family home, Saltwood Castle in Kent, confessed philanderer Mr Clark said: 'I deserve to be horsewhipped. I have changed my ways and I am now a reformed character.'
Later, he expressed his regret at what had happened and added: 'I do not want to cause the Harkess girls any distress. I wish that they would take the money Max Clifford (their publicist) is raising for them and push off.'
Valerie and Josephine Harkess denied they were in Britain to cash in on the row. Although they stand to make an estimated pounds 150,000 from television and newspaper interviews arranged by Mr Clifford, they claim they are primarily motivated by their desire to 'put the record straight' following references to them in Mr Clark's diaries, published last year. In the book Mr Clark refers to Mrs Harkess and her daughters as 'the coven'.
Mr Clifford said Alison, the wife of Sergei Kausov, former KGB agent and ex-husband of Christina Onassis, is estranged from her family and wants no part in the media coverage.
On Sky News, while her mother looked on, Josephine claimed Mr Clark had 'showed his willy constantly' to her and her sister when they were in their early teens.
The family blamed Mr Clark for the 'enormous personal trauma' they were going through. But Mrs Harkess admitted she had continued her affair with Mr Clark even after she discovered he had seduced her daughters.
Earlier, Mr Clark said horsewhipping would be a fitting punishment because 'it's nice and old fashioned'. He then admitted with characteristic understatement: 'I probably have a different sense of morality to most people.'
Not everyone thought Mr Clark should be punished. Andrew Roberts, a historian and friend said: 'It's a heroic thing to do - sleep with a mother then her two daughters. He must have gone up in everyone's estimation. '
Last night Piers Morgan, editor of the News of the World, which broke the story, said vengeance, not money, was the main motivation for the Harkess family.
'They are a very wealthy family, and certainly the amount of money we paid them was nowhere near what people would normally think we might do. Their driving force is to humiliate him.'
Media circus, page 3
Mark Lawson, page 19
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