As rumours do, it spread quickly. And by the time an official statement quashed the speculation it had already been reported as fact by journalistic luminaries, including Jon Snow of Channel 4 News.

A single sentence from a fake Twitter account claimed Piers Morgan had been suspended by employer CNN following allegations that he might have been involved in phone hacking during his time as a tabloid editor.

The story was wrong and Snow was forced to apologise. But the fact so many people were prepared to believe it illustrates a simple fact about the former editor of the News of the World and the Daily Mirror, who has embarked on a new career in the US: the number of Britons willing him to fail far exceeds those happy to see him succeed.

Morgan responded to claims that he had knowledge of phone hacking with typical gusto, taking to Twitter to lambast his accusers as "liars, druggies, ex-conmen and bankrupts". Conservative MP Louise Mensch, who said in parliament last week that Morgan had admitted knowing about the practice of procuring stories by intercepting mobile phone messages, conceded on Friday she had been wrong.

After an interview on Desert Island Discs in which he discussed tabloid techniques with Kirsty Young had come to light, he issued a statement through his principal employers in the US, insisting he had not admitted wrongdoing.

But in The Insider, Morgan's best-selling account of his life as an editor, penned after he left the Mirror, there are many hints about the techniques "red tops" – or the people who supplied them – used.

On 28 July 2000, for example, Morgan writes the paper was "offered a dodgy transcript of a phone conversation between [Princess Diana's former lover] James Hewitt and Anna Ferretti today".

The entry for 26 January 1998 describes how the Mirror had run "another load of stuff from Benjamin Pell today, centring on Elton [John]'s 'cash crisis' ".

Pell was notorious for going through the rubbish of the rich, famous and powerful – a technique which earned him the nickname Benji the binman.

In 1995, when Morgan was still at the News of the World, on 9 April the paper's legal team were worried about running a story concerning an affair a Tory MP, Richard Spring, was having because his mistress had tape-recorded their conversations. Morgan wrote: "I ignored them, confident that Spring's so bang to rights it doesn't matter how we banged him."

The key question for Morgan now, seven years after he was sacked as editor of the Daily Mirror, is whether he can survive the media storm currently raging on both sides of the Atlantic.

In normal circumstances a story about the underhand, and sometimes illegal, practices of British tabloids might be expected to blow over quickly, particularly in America.

But the controversy over phone hacking at the News of the World, and the crisis it prompted at Rupert Murdoch's News Corp, dominated the headlines for weeks in the US, where Morgan is a household name.

His weekly CNN show is watched by millions and he replaced his friend Simon Cowell as a judge on America's Got Talent, the show which transformed him from a little-known Brit into a star.

If there is an appetite in America for stories about his tabloid past, it is partly because he has created one by pursuing a campaign of relentless self-promotion. CNN has spent heavily marketing Morgan as a replacement for Larry King and it is unlikely to drop him on the basis of allegations about his conduct at the Mirror or, before that, at the News of the World, where he became the youngest ever editor at the age of 28 in 1994.

All the signals emanating from CNN's corporate headquarters in Atlanta, Georgia, are that his job is safe. A CNN source who is close to Piers said last night: "The show is fine. Everyone's really happy with it. The number is up year to date from where Larry [King] was. The show is only six months old and it gets pick up from the press every single day".

A CNN spokesperson last night: "We continue to be supportive of his programme." CNN also pointed out that audiences for Piers Morgan Tonight are up 10% compared to what they were when the show was hosted by Larry King.

But senior media industry insiders in New York, from where Morgan's show is broadcast, say his star is no longer rising.

"The executive who hired him, CNN president Jon Klein, was fired right after [Morgan joined]," claims one source,

That is significant because Klein, who left in September last year, months after Morgan agreed a deal with the cable news channel, had championed him.

The ratings for his CNN show are slightly better than those Larry King enjoyed – up about 12% – but significantly lower than when Morgan started.

The same source says insiders at CNN are also irritated by the number of shows that are pre-recorded due to Morgan's commitments to America's Got Talent, which is filmed in LA but has also gone on the road across the country. "He's phoning in the show," he said.

Sources close to Morgan deny this, and say interviews with big stars including Beyoncé are recorded so they can be trailed weeks before they are aired. However, the buzz that surrounded Morgan's arrival has faded.

"The other thing to bear in mind is that no one talks in the media about Piers's show," the insider said.

"Some magazine and newspaper editors the other night [said] it just isn't on their radar screen at all any more. It doesn't make or break news."

Morgan has never been shy of expressing an opinion and his own words have come back to haunt him. He is also viewed unsympathetically by many of his peers.

The New York source added: "There is no love lost in the press here at all for Piers. There is a feeling in the media that he is a guy who is very arrogant and a lot of people are lining up to kick him."

It was the US that broke Morgan the first time around. American shareholders in the Mirror's owner, Trinity Mirror, were by far the most vocal in calling for his head when he published fake pictures of British troops allegedly abusing Iraqi prisoners.

They had been angered by Morgan's unremittingly hostile coverage of the war in Iraq in the months that led up to that mistake. America also gave Morgan the chance to remake himself.

But if it emerges during the course of the criminal, parliamentary and judicial inquiries into hacking in Britain that he was in any way implicated, it will be America that finishes him off.