ITV News was today banned from a press conference by Avon & Somerset police after broadcasting a critical report on the force's investigation into the murder of Joanna Yeates.

Avon & Somerset constabulary has also complained to the media regulator, Ofcom, about what it claimed was the "unfair, naive and irresponsible reporting" of the case on ITV1's News at Ten last night.

The broadcaster's reporters were told they would not be allowed into today's briefing on the murder of the landscape architect in Bristol last month, but were given no further detail about why.

Last night's News at Ten ran a report critical of the force's investigation into the 25-year-old's murder, claiming that police were no closer to finding her killer 10 days after her body was found.

Reporter Geraint Vincent questioned whether the Avon & Somerset constabulary's inquiries had followed procedure. A former murder squad detective, interviewed for the programme, claimed that the police were failing to conduct "certain routine inquiries", such as painstakingly sweeping the murder scene for fresh evidence.

Vincent reported: "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 News at Ten report also said the police were giving "mixed messages" on the possible circumstances of Yeates's death.

"We have made a complaint to Ofcom in respect of the unfair, naive and irresponsible reporting on the ITN 10 o'clock news yesterday evening," Avon & Somerset constabulary 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."

David Mannion, the editor-in-chief of ITV News, called the force's decision "irresponsible" and claimed it had developed into "an issue about the freedom of the press".

"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.

"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," he said. "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."

ITN, which produces ITV News, said it was "hugely disappointed" by the police's decision to "exclude" the broadcaster from its press conference.

"This decision will result in millions of viewers not being able to see new evidence or hear the latest police calls for witnesses," an ITN spokesman said.

"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."

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