'This is nothing but the cheapest possible way for marketing the new biography of Imran Khan,' Hasan added.

Author Sandford, who interviewed both Khan and his English ex-wife Jemima, claims a source told him that Bhutto was 21 and in her second year at Lady Margaret Hall college in 1975 when she became close to Khan.

A mutual acquaintance reportedly told Sandford that Bhutto had been 'visibly impressed' by Khan, and that she might have been among the first to call him 'the Lion of Lahore'.

Sandford told the Daily Mail: 'In any event, it seems fairly clear that, for at least a month or two, the couple were close. There was a lot of giggling and blushing whenever they appeared together in public.'

'It also seems fair to say that the relationship was 'sexual', in the sense that it could only have existed between a man and a woman. The reason some supposed it went further was because, to quote one Oxford friend: 'Imran slept with everyone',' he added.

Khan, currently on holiday with his children, has not yet read the book touted as an official biography, but told the paper: 'Yes, I was interviewed, but I know nothing about the rest of what has been written. So it is not official.'

'It is absolute nonsense about any sexual relationship or my mother and an arranged marriage. We were friends - that's all,' Khan added.