Lord Ashcroft has gained a reputation as a buccaneering and somewhat controversial businessman. With his love of yachts and private planes, he is known in the financial world for his jet-set lifestyle. But with dual nationality and a diplomatic passport granted as Belize's former ambassador to the United Nations, he was not widely known outside business and Tory circles.
When the tycoon accepted the post of treasurer to the Tory party, though, a wider spotlight was shone on his social and business affairs. Suddenly, journalists began sniffing round the Central American tax haven of Belize, where Lord Ashcroft's business empire is based.
While Lord Ashcroft wrote cheques for millions of pounds to the Tory party and persuaded donors to reach into their pockets to support William Hague, unflattering stories began to appear in the press about the source of his cash and the nature of his business dealings.
Foreign Office documents detailing a row with diplomats at a party Lord Ashcroft had attended and references to his "laundry arrangements" were leaked to the press.
The Times ran a series of articles about his financial dealings in Belize in 1999. It alleged his name had been mentioned in US Drug Enforcement Administration files, stories that Lord Ashcroft said were extremely damaging and part, he claims, of an orchestrated campaign to discredit him.
"Truth didn't matter. It was, 'If you couldn't get any facts, smear' and 'If they were able to get my scalp then the end justified the means'," he said.
The Tory peer said he believed the campaign against him had "suited" both The Times and the government of the day and that he was battling gainst a "two-headed monster" that attempted to smear him while he was Tory treasurer, a post he resigned in 2001 after Mr Hague stood down.
Now his retaliation is clear: a relentless campaign to pick off, individually, those behind the leaks to the press and those who aided what he claims was a press campaign against him.
"We all express things differently. My passion is in my actions. It's not something that I will let wind me up. I remain angry," he said.
One by one, Lord Ashcroft, like a sniper, is aiming at those behind the leaks, and has his sights trained on officials at Downing Street, senior Foreign Office staff and even former ministers. He says he is patient enough to wait years until the full picture emerges.
His approach is ruthless and has already claimed victims. In the United States, the official at the DEA who obtained sensitive agency files that found their way to The Times was earlier this year sentenced to a year in prison.
The billionaire peer admits he helped the DEA to with its inquiries into Jonathan Randel which led to his conviction.
"We worked together to be able to track him down," Lord Ashcroft said. "But what was important to me was that in court in Atlanta the DEA stated I had never been under suspicion for anything and when they issued their press release on the conviction of Randel they made the statement that I had never been under any form of investigation."
Lord Ashcroft was granted a peerage in 2000, but only after Mr Hague challenged a decision by the political honours scrutiny committee to block it. The peer seems to revel in his reputation as a ruthless opponent, admitting that he makes "a better friend than an enemy".
In Westminster, rumours were rife that at the height of intense media coverage against him that he hired a private detective to tail a Times journalist who had written about him.
He smiles quizzically when asked if this is true. "I wouldn't wish to alter the mystique of that by accepting or denying it, but there is no doubt I will do whatever it takes and people shouldn't underestimate that," he warns.
Lord Ashcroft's immediate quarry is the person who he claims obtained secret records about his donations to the party, information that found its way to The Times. He plans to name names and pursue the matter through the courts. The Times declined to comment on Lord Ashcroft's allegations.
After starting what may have been the costliest libel action in history, Lord Ashcroft has since settled his libel claim after a meeting in London with the proprietor of The Times, Rupert Murdoch.
"We just met at his apartment in London, just the two of us. I would describe it as an excellent meeting. It suited us both at that particular point in time, and what was important to me is that he was prepared to put on the front page of The Times the fact that neither I nor any of the companies I was involved with had ever been even under suspicion," he said. "Therefore that, at that time, was one step of an admission by The Times, but it was important for me that we went further."
Lord Ashcroft says he did not, as rumour has it, ask Mr Murdoch to sack Sir Peter Stothard, the former editor of The Times who stepped down last year.
"I don't know what was in Murdoch's mind at that time, so it is shrouded in mystery and I don't think we have yet known the full truth," the peer said.
But, even though he has settled his libel action, he is determined to pursue his grievance against those he believes were behind the campaign to target him.
He believes Clare Short was involved in a politically motivated campaign against him when, as International Development Secretary, she suggested that Belize be denied debt relief unless his tax concessions with the state were curtailed. He has obtained internal government documents under freedom of information laws that include a personal note from Ms Short about cancelling Belize's "Commonwealth debt initiative". "Clare Short's department denied Commonwealth debt relief to Belize unless the Belize government reneged on my tax concessions in Belize. There were references to [her] saying, 'Tell the Belize government to stop "messing about".' It was a total campaign," Lord Ashcroft said. "There was no reason to deny Belize debt relief."
Some have questioned whether his decision to continue his campaign may not fuel the controversy. But Lord Ashcroft seems almost to revel in the oft-quoted description as the "controversial former Tory treasurer".
"I think I have become accustomed to that tag and would say that 'controversial' doesn't always have a negative connotation to it," he said.
"There have been many people in history who have been controversial. After 30 years I obviously can't shake it off and if I can depart this life in my 90s still being controversial then I suppose that's character by that time."