Katie Couric, who has read the evening news on CBS for five years, left the safety of her Manhattan studio yesterday for Baghdad to report on progress in Iraq eight years after the United States-led invasion.

It is the kind of assignment that is meant to remind viewers that highly paid anchors are more than just pretty faces.

This may be moot for 54-year-old Couric, however. Recently anointed the 22nd most powerful woman in the world by Forbes by virtue of her stewardship of the CBS Evening News - above both Melinda Gates and Madonna - she is reportedly on the brink of surrendering to poor ratings and throwing in the towel.

Already, the focus of speculation has turned to what she will do next and who will replace her.

It should not have turned out this way. It was David Letterman, the veteran late-night man on CBS, who reminded Couric when she appeared last month on his show that American news anchors are expected to "ride into the sunset" with their jobs.

"Once you take that anchor chair, that's what you do," he said. Among those he doubtless had in mind was the late, great Walter Cronkite, also of CBS News.

Couric, moreover, was seen as a mould-breaker when she debuted at CBS in 2006. Defecting from NBC after 15 years co-hosting the breakfast Today Show, she was the first woman to anchor a network evening news bulletin alone. Her mission: to lift the show from its number three spot behind both ABC and NBC.

If ratings are the final arbiter of success, however, the appointment of Couric, who has never shaken off her reputation as a "perky" presence on TV as against one with the kind of gravitas associated with news anchors, has not worked.

Her programme is still third in the ratings. Indeed, audience numbers in the first quarter of this year were worse than at any time for CBS since 1992.

It is a source of continuing frustration for CBS, which historically dominated serious news programming. After Cronkite came Dan Rather, who relished reporting beyond the studio; the network is also still home to 60 Minutes, the current affairs show without peer in the US.

Neither Couric nor her representatives have publicly confirmed that she is to leave her position. Little, however, has been done to quash the speculation that it will happen when her current US$15 million-a-year ($19.5 million) contract expires on June 4. The Associated Press news agency has reported her imminent departure as fact.

"We're having ongoing discussions with Katie Couric," Sonya McNair, a CBS News spokeswoman, said. "We have no announcements to make at this time. Until we do, we will continue to decline comment on rumour or speculation."

However, in an interview with the New York Times, Couric came close to conceding that change was afoot. Challenged about reports that she has been talking to her old NBC boss, Jeff Zucker, she replied: "We talk a lot and, yes, we've been discussing the possibilities. That's true."

- Independent