Who's that girl? The assassin from Shropshire storming Manhattan

They're not quite like buses, but no sooner does one coveted New York media job become vacant then up pops another.

News that Larry King will be replaced on CNN after 25 years by Piers Morgan has been followed by the departure of Richard Johnson as editor of Page Six, the infamous gossip column in the New York Post. He too had been in place for a quarter century and, in what news editors will see as the makings of a trend, has also been replaced by a Briton, albeit a much less well known one, Emily Smith, 29, a reporter from Shropshire.

The naming of a new diary editor would scarcely make the media pages in London, but it's a measure of Page Six's importance that The New York Observer has already rushed out a 2,000-word Smith profile.

David Yelland, a former editor of The Sun who joined from the Post, where he was deputy editor, says it is hard for the British to understand the significance of Page Six to New Yorkers. "It is a brand within a brand," he says, "The nearest thing in the UK is the [Evening Standard's] Londoner's Diary. When you get your name in Page Six – and they put the names in bold – you know you have arrived."

Created by Rupert Murdoch after he bought the New York Post in 1976, Page Six has grown to overshadow the paper that houses it. The column charts the ups and downs of Manhattan's glittering classes and is pored over by people who would never normally consider themselves interested in gossip.

Unlike British gossip columns, Page Six's subjects include not just celebrities but figures from the media, finance, lawyers and film producers.

"A lot of the people written about are New York figures that nobody outside the city would care about," says Rebecca Guinness, a former Vanity Fair writer, "There's a weird shame to being in it but people also get a massive thrill from it. For just 25 cents you get this amazing update on what is going on."

The appointment of a Fleet Street hack will raise a few eyebrows on the Upper East Side, where they like to think of Page Six as more sophisticated then our celebrity-obsessed equivalents. And while Johnson, who has been lured away to a $1m post at The Hollywood Reporter, was a well-known society figure, Smith is a relative newcomer, joining the column only a year ago.

But she is familiar with the New York scene, having arrived as US editor for The Sun in 2005. Before that, she was No 2 on the Bizarre column, having quickly impressed editors when she joined the news desk aged only 21. After Liverpool University, she spent a year at The Shropshire Star before breaking into Fleet Street.

"Emily has the perfect attributes for a gossip columnist," says Piers Morgan, who edited Bizarre between 1989 and 1994, and knows Smith. "She looks completely unthreatening, so that when people meet her at parties they think she is harmless, but underneath she is a ruthless and steely assassin. She is like a female James Bond."

Being around 5ft tall may also be useful. "I always say the secret to being a tabloid gossip columnist is not to appear how people imagine you should," says Dan Wootton, the showbiz editor of the News of the World. "Emily is intelligent, well-spoken and well-presented: she is just the kind of person you would want to have at your party. There's a popular misconception about showbiz reporters, but I was at the Oscars with Emily and she was invited to all the best parties."

While some may sniff at her tabloid credentials, the roll call of influential figures who started at The Sun's Bizarre column – Andy Coulson, Piers Morgan and current Sun editor, Dominic Mohan – suggests it is a formidable training ground.

"You need a lot of guts in this job," says Wootton. "You have to be confident in yourself and not necessarily worry about social norms or about what people think about you. It's also relentless: you have to work 24 hours a day, seven days per week, and sometimes you operate on two hours' sleep, and in a tough newsroom environment. You have to be dogged and committed but you also have to build up relationships with people while you are writing about them, which can be difficult."

Starting out in the industry is the biggest challenge, says one former showbiz hack who wishes to remain anonymous. "There is no training. On your first day the desk will ask you to do the worst thing they can think of. I had to doorstep someone who had just lost a child. They try to give you a death knock quite quickly because they want to know if you can hack it. It's all about how brave you are and whether you can do something or not. None of them can write for shit."

While Smith, who declined to comment for this piece, has already proved her story-getting abilities, some may wonder whether she will share her predecessor's magic touch. "She is inheriting a crown jewel," says one former colleague. "Richard will be hard to replace. The question will be whether she is sophisticated enough to understand the market, because the difference between Page Six and Bizarre is chalk and cheese."

Others, such as Dan Wootton, are more optimistic. "Yes it's more society-led, and more media- and business-led compared to a tabloid gossip column, but Emily knows that. There's no way she'd have got the job if she wasn't up to it."