Mr Sethi has been infuriating the Pakistani authorities ever since returning home from Cambridge more than 25 years ago, midway through a doctorate.
The late prime minister Zulfikar Ai Bhutto jailed him in 1975 for pro- democracy protests. After his release he set up in publishing, and the military dictator Zia ul Haq threw him behind bars in 1984 for publishing a book on the United States' role in Pakistan.
With the new liberal mood that came in after Zia's death in 1988, he and his wife, Jugnu, set up the Friday Times, the weekly paper he still edits from a cramped office off the Mall in central Lahore. But his latest bout in jail - he was dragged from his house in the middle of the night last month, beaten up and held incommunicado for three weeks - was said to be punishment for giving an interview to a BBC team making a film about corruption in Pakistan.
Najam Sethi is free again, but it is a provisional, uneasy, tentative sort of freedom. On 17 June he, Jugnu and their two children stayed as usual at a relative's place. "Since I was abducted, Jugnu and the kids haven't slept at the house," Mr Sethi says. "We don't feel safe any more."
The feeling is not necessarily irrational. A senior journalist who Mr Sethi says is close to the intelligence agencies gave him a friendly warning. "Don't think this is over, Najam. They have taken it all personally and are very vindictive," he said.
Earlier in the day he was in the office of the Friday Times, but the mood there, too, was grim. "The staff look anxious," he says. "One correspondent has taken 'long leave'. Another has fled the country on some excuse. The phone lines are all tapped."
Friday 18 June. Due to leave Pakistan in less than a week to fly to London, Mr Sethi does not even have a passport. It was confiscated by Inter-Services Intelligence Directorate (ISI), Pakistan's spy agency, when they arrested him. He rings them up to ask for it back. They hedge. We'll call you, they say. Mr Sethi calls Amnesty to inform them of the hitch.
Saturday. The children are packed off to the in-laws' farm for the weekend, where they will be safe. Friends and relatives come over in solidarity and out of curiosity. At dinner is Mr Sethi's lawyer, Dr Khalid Ranjha, a former judge of the Lahore high court and president of the Lahore Bar Association. Why not file a writ demanding the passport back, Mr Sethi asks. Jugnu says: "No, let's wait for the ISI to say yes or no."
Monday: At last, some good news. The ISI call to say that he will get his passport back today at 6pm. "Does that mean I can go to London to receive the award?" Mr Sethi asks himself. "What if I am on the Exit Control List? Shall I book my seat?" He books the seat.
Tuesday: A popular form of official harassment in Pakistan is to spray perceived enemies of the state with spurious tax demands. This has been happening since Mr Sethi's arrest. The Sethis' house has also been "attached" by the tax department, and Jugnu's bank accounts seized. More tax demands arrive today.
Tonight the Sethis sleep at home again. The children take a lot of persuading. "I have to leave for the airport early tomorrow morning," Mr Sethi tells them. They all squeeze into a single room.
Wednesday: Day of departure. Up at 5am, Mr Sethi and his wife are at the airport by six. Mrs Sethi waits outside while her husband goes in. "Keep your mobile phone on, just in case," she tells him. "Call me before you board the aircraft."
The customs people are friendly and sympathetic. But just as Mr Sethi is waved into the immigration lounge, someone in an official uniform says, "Step this way please."
"He waved me to a sofa," Mr Sethi relates. "'May I have your passport please?' 'Of course'. He went away. Came back with two others in tow. 'You can't leave, sir, you're on the ECL [Exit Control List]. We're sorry. Orders are orders.'
'Who gave the orders?' I demanded to know. Silence. Then someone explained, 'The IB [Intelligence Bureau] ordered this on 2 June.' 'But that's the very day I was set free and all charges were dropped,' I replied'. " Kafka lives.
Mrs Sethi calls on the mobile and he tells her what has happened. "Come out quickly", she says, but before he can do so an official says, "Could I have your passport for a moment, please." Fifteen minutes later, Sethi is informed that the IB intends to retain the passport. "I demand an explanation. Silence. 'Go home, sir,' says an official, 'you'll get your passport back when we're ready to give it to you'."
Thursday: More tax notices arrive. At the last count the Sethis now had 50 between them. And today, an unexpected wrinkle: a ruling party MP has filed a petition before the chief election commissioner demanding that Mr Sethi be declared a non-Muslim and disenfranchised.
At the end of all this, Sethi says: "I can't believe this is happening to me." Peter Popham