Britain’s ITV News was on Wednesday banned from a police press conference after running a report criticising the police’s handling of an investigation into the murder of Joanna Yeates, a landscape architect whose body was found on the outskirts of Bristol last month, the Guardian newspaper reported.

Avon & Somerset police have complained to Britain’s broadcast media regulator, Ofcom, about what they have branded “unfair, naïve and irresponsible reporting” of the case on ITV1’s News at Ten on Wednesday evening, the newspaper reported.

In the critical report, ITV News claimed that police had made no progress on finding the killer 10 days after Yeates’ body was found, the Guardian said.

During the report, an ex-murder squad detective claimed, in an interview, that the police were not performing “certain routine inquiries”.

The Guardian quoted the ITV News reporter as saying: “There may be good reasons why certain routine inquiries may not have been followed. But while this investigation has arrested and released one suspect, 10 days in it is still apparently short of evidence.”

The police said in a statement: “As we are still awaiting a response to our complaint it would be inappropriate for us to comment any further at this time.”

“A live murder investigation has been underway now for just 12 days and the media have played an important role in helping us to appeal for witnesses. While we appreciate the support we have received so far from most of the media we must step in if we feel coverage will hamper the investigation. Our primary aim will always be to secure justice for Joanna.”

ITV News editor-in-chief David Mannion suggested that the police’s decision was “irresponsible” and added that it had become “an issue about the freedom of the press”, the Guardian reported.

“We stand by our story and we also stand by the procedure which the police have now taken [to complain to Ofcom]. If Ofcom decides to uphold that complaint we will respect that,” Mannion told BBC Radio 4’s The Media Show, according to the Guardian.

“There’s an issue in the interim period if we have a situation where there’s numbers of the press summarily banned from press conferences – and that’s what happened this morning before the complaint was made,” the Guardian quoted him as saying. “We made numerous attempts to contact Avon & Somerset police – between eight and 10 – before the programme went out and didn’t get a single response.”

A spokesman for ITN, which produces ITV News, said it was “hugely disappointed” by the police’s move to “exclude” the broadcaster from the briefing.

“This decision will result in millions of viewers not being able to see new evidence or hear the latest police calls for witnesses.”

“Our coverage has helped maintain awareness of this case, and we strongly disagree with Avon and Somerset constabulary’s attempt to censor what information we can broadcast.”

“Avon & Somerset constabulary’s decision to ban ITV News follows reports on last night’s ITV News at Ten which raised apparent inconsistencies of the police’s handling of some elements of the case. The force was contacted numerous times ahead of broadcast but Avon & Somerset constabulary did not use this opportunity to register any issues or raise a complaint with ITN.”

IPI Press Freedom Manager Anthony Mills said: “We are concerned at the possibility that ITV News may have been excluded from the press conference because the police did not like what it had to say about the investigation, and, most importantly, before the outcome of the complaint launched with Ofcom. We urge the authorities to recall that news outlets have a right to report critical views, even of police investigations, and that in the absence of any criminal laws having been broken, no summary action should be taken before the ruling, by Ofcom, on the complaint.”