The Pakistani nuclear scientist who labelled me a "Hindu bastard" is the focus of renewed interest by US and British intelligence services for his role in using Libyan slush money to further his country's weapons programme.
Indeed, Western displeasure with Khan's activities is so considerable now that the government-supplied guards who used to patrol his bungalow in Islamabad's fashionable F block have been withdrawn and the 67 year-old metallurgist is vulnerable to the inquiries of journalists, diplomats, or investigators from all parts of the world.
The questions they all want to direct to the pudgy-faced Bhopal-born scientist is what information he passed on to other governments about the wherewithal for making nuclear bombs that could one day be used to blow the rest of us off the face of this planet.
Last weekend, The Sunday Times in London asserted, controversially, that Libya was far closer to nuclear-testing status than had been previously suspected. If so, Khan's pivotal role is an issue worth considering in detail.
More important than Libya, though, is the information that Khan passed on to North Korea and Iran, offering in vain to do the same for Iraq, and thereby transforming Pakistan into the world's most terrifying nuclear proliferator since the dawn of the nuclear age.
It was my misfortune to cross swords with Khan in 1979 during the course of research for a book on nuclear proliferation. An article on Khan, entitled, 'How Dr Khan stole the bomb for Islam', was duly published in The Observer, London, the newspaper for which I then worked, and immediately attracted Khan's fury.
Three months earlier, Dutch scientists based in the small town of Almelo had briefed me on the activities of their former Pakistani colleague who had worked with them to develop a highly classified process of enriching uranium. Suspicious of Khan because of the questions he asked and the copious notes he made, they were convinced that he would pirate the Almelo technology and reproduce it in Pakistan.
How right they were! After India's first nuclear test at Pokhran in 1974, Khan told Pakistan's then prime minister, Zulfiqar Ali Bhutto, that he could match India's effort, and even surpass it, provided he had the funds and the unqualified backing of his government.
Bhutto gave him both. He even introduced him to Libya's Colonel Muammar Qadhafy who sent suitcases stuffed with dollars to Islamabad in exchange for Bhutto's promise, through Khan, that the technology of the top-secret uranium enrichment plant being developed close to Rawalpindi at Kahuta would one day be transferred to Tripoli.
So began the great nuclear adventure of marrying pirated Dutch enrichment technology to the warhead designs that would later be imported from China.
When details of this project leaked out to The Observer in 1979, Khan's fury was unimagineable. Some of the epithets he used to describe The Observer reporting team included words like "agents" and "bastards". The other expressions he used are too sordid to repeat even now, 25 years later.
Worse was to follow a few years later when veteran Indian journalist Kuldip Nayar, later to be a member of the Rajya Sabha, scored a worldwide scoop by securing an exclusive interview with Khan at his Islamabad home. As Khan's wife Henny served tea, cake, and biscuits to the two men, Khan confirmed the gist of my earlier investigation, namely that Pakistan was engaged in a massive clandestine effort to become the world's next nuclear power.
Nayar's interview was published in The Observer in 1987, alongside my analysis of how Pakistan was now a "threshold" nuclear power.
This time Khan's reaction went even more out of control. In a letter of complaint to the British Press Council, he described the Nayar interview as "false" and "concocted", but his special venom was reserved for me, the "Hindu bastard" who had dared to single him out for so much attention.
The complaint was duly rejected, but news of Khan's letter had spread like wildfire and the "Hindu bastard" on The Observer staff was the subject of many mocking jokes from his colleagues.
Later, President Zia-ul-Haq asked me if I retained any hurt about Khan. When I replied in the negative, General Zia smiled and said, "Actually, he's not such a bad fellow."
I have never had a chance to find out what Khan really is like. For years the Pakistani government denied he even existed. When he was later confirmed as a national hero, he became as inaccessible to the foreign media as Mao Zedong.
But in the changed world of the 21st century, Khan's future is as uncertain as that of anyone else. He may be dragged off to a 're-education' camp for rogue scientists, or if he is lucky, he may be allowed to live out the rest of his life in respected oblivion. If we should happen to meet, and nothing would make me happier, I will know that even 'Hindu bastards' have a God who smiles upon them.
Photograph: Farooq Naeem/AFP/Getty Images
