THE SNIFFER dog, a spaniel, was the first clue. Then the small posse of police wearing earpieces and flak jackets confirmed the suspicions. The target was heading for platform five at King's Cross station.
David Blunkett walked briskly on to the platform with his dog, flanked by the armed police escort and his personal bodyguards, who always travel with him. The former home secretary has many enemies.
There are the al-Qa'ida fanatics who threaten a terrorist attack on the forthcoming election and would view the man who ordered the detention without trial of suspects in Belmarsh as a prime target.
There are the cabinet ministers he laid into in the unauthorised biography - Patricia Hewitt could not "think strategically", John Prescott "never quite cottoned on", and Charles Clarke under whom the education department, Mr Blunkett's old portfolio, had "gone soft".
There are the Quinns, the businessman and the American socialite, entangled in the "personal tragedy" of Mr Blunkett's traumatic private life. And there is the media, which door-stepped Mr Blunkett day and night, including Christmas Day, after his two-year affair with Kimberly Quinn broke into the open.
Mr Blunkett stops at the carriage entrance for a photograph. "Do you want one of me in the doorway?" The police twitch at the delay, and his dog, Sadie, a black Labrador-retriever cross, and half- sister of Lucy, his former guide dog, faithfully puts a paw on the step.
We are in first class, with neighbouring passengers reconciled to having a media target in their midst. The train is going north, but this is the Blunkett Express back to the front line.
He has had a week of interviews, including Breakfast with Frost, covering his views on Englishness, the need for a different style of manifesto, and his tangled personal life - he denies ever saying "Kimberly was the love of my life" but she was clearly that. It all signals that, having licked his wounds for three months, the MP for Sheffield Brightside is ready for the big political stage again.
"I feel strong again," he said. "It's all hands to the pump and that is what I am doing with a vengeance. I would like to come back, but I have to earn it. That means doing the graft of getting around the country."
He has discussed with Tony Blair the role he will play in the election - he will be leading the campaign on ID cards, which the Tories now oppose - although he insists he has not been promised a cabinet job, despite speculation that he will be brought back to oversee delivery, a role currently in the hands of the Deputy Prime Minister.
His reputation for being tough - critics say authoritarian - means he will be a box-office draw. Mr Blair will be happy to see him turning the tables on the Tories, who stand accused of being soft on terrorism for opposing the Prevention of Terrorism Bill earlier this month.
Mr Blunkett is convinced that when a series of current court cases are completed, the public will be on his side. "People might get a shock; those who say there was no threat will have to eat their words," he said. "There hasn't been an attack on Britain because of the work of the intelligence and security services.
"People will look back and say `thank goodness we protected ourselves', not [just] because we prevented individuals and their network from attacking, but because we made a difficult environment for them and were not a soft touch."
Mr Blunkett said he wanted the public to be "alert but not alarmed", in contrast to Sir John Stevens, the former Metropolitan Police commissioner who said an attack was "inevitable".
But he has no doubt that al-Qa'ida will target the election campaign. "Given what happened in Madrid a year ago, we would be foolish not to take this seriously," he said. But there has been no specific threat to bomb the …