A criminal pardon U.S. President Donald Trump personally delivered to Conrad Black over the phone amounts to complete exoneration, the author and former media mogul said on Thursday.

In an interview with The Canadian Press, Black also said he had yet to decide whether to try to regain the Order of Canada, of which he was stripped following his now undone conviction in the United States.

"This completes the destruction of the spurious prosecution of me," Black, 74, said. "It's a complete final decision of not guilty. That is finally a fully just verdict."

On May 6, Trump phoned Black at his home in Toronto to announce the pardon for his 2007 convictions on obstruction of justice and fraud for which he spent more than three years in a federal prison in Florida. The convictions related to what prosecutors called his scheme to siphon off millions of dollars from the sale of newspapers owned by Hollinger Inc., where he was chief executive and chairman.

Under U.S. law, a pardon represents full legal forgiveness for a crime.

Declines comment on claims of 'back-scratching operation'

Black said he initially thought he was being pranked by a brilliant impersonator but quickly realized the person on the other end of the line was Trump himself. The two men have long been acquaintances and Black recently wrote a glowing book called Donald J. Trump: A President Like No Other.

If I was one of these people who slagged him off and accused him of being an asset of the Kremlin and a traitor to the United States and so forth, I would not count on him having bestirred himself to do anything about it. - Conrad Black

Their relationship, which Black described as good but not intimate, was secondary when it came to the pardon, he said.

"If I was one of these people who slagged him off and accused him of being an asset of the Kremlin and a traitor to the United States and so forth, I would not count on him having bestirred himself to do anything about it," he said.

"To those who say it was just a back-scratching operation and it's just a payoff to me for being a supporter, I would decline to comment on that."

Black has always maintained he was the victim of an unjust U.S.criminal justice system. The pardon from the highest legal authority in the United States was a "great comfort," he said, but Trump went even further.

"It was a bad rap and unjust verdict, and I should never have been charged," Black cited the president as telling him.

One practical impact of the pardon is that Black is now free to travel to the United States, which he called a "great country."

White House praises Black for 'tremendous contributions'

While Black could have applied for a special entry waiver, he said he never did because of the "outrageous way" the system treated him.

The conversation with Trump, he said, was "most cordial" and the president expressed a wish to see him again. However, Black said his only plans are to spend time in England this summer and visit New York in September.

What's important, he said, is that the pardon signals the end of a long, dark chapter.

"It was a very unpleasant business for a long time. It's no day at the beach having the government of the United States and its Canadian quislings on your back for years on end. I survived it and we drive on."

Conrad Black, right, is shown with his wife Barbara Amiel Black and attorney Miguel Estrada as they leave federal court in Chicago on June 24, 2011. (Associated Press)

On Wednesday, the White House praised Black in a statement as having made "tremendous contributions" to business, and political and historical thought. Black's pardon application included support from such well-known luminaries as former U.S. secretary of state Henry Kissinger, conservative pundit Rush Limbaugh and rock star Elton John.

Black's conviction led to a rare revocation of his Order of Canada in 2014. He said he hadn't decided whether he would try to regain it.

"I'll think about it," he said. "That whole thing was so disagreeable, I don't know if I want to reopen it."

Rideau Hall had no comment.

'Why should I care?'

Similarly, Black said he had yet to decide whether to try to overturn an Ontario Securities Commission ban on corporate involvement. The commission, which he referred to as the "Office of Stupidity and Cowardice," was "absolutely asinine" in how it treated him, he said. The commission also had no comment.

Black, who renounced his Canadian citizenship in 2001 after a well-publicized fight with then-prime minister Jean Chretien over accepting a British peerage, remains a permanent resident of Canada.

He said he might try to regain his citizenship "one of these days"and the presidential pardon should make that easier.

After all, he said, he has now been back in Canada seven years without a parking ticket while paying a "lot of taxes."

"I believe it would not be a controversial or difficult thing to achieve it," he said of regaining Canadian citizenship.

"I suppose there are a few people in this country snorting around in the undergrowth that I shouldn't be here. But I don't think it's a widely held view. People will say what they will say. When you've been through what I have, you don't much pay attention to what the jackals have to say about things.

"Why should I care?"