The Metropolitan Police has admitted the decision to close the phone hacking investigation was taken too quickly “with a defensive and closed mindset”.

Neil Garnham QC, representing the force at the Leveson Inquiry, said in a closing submission yesterday the force was willing to acknowledge mistakes and learn from its errors.

The original investigation – Operation Caryatid – was closed down in 2006 and a bid to reopen it in 2009 was quashed by then assistant commissioner John Yates. His review of the investigation took place over the course of one day.

Garnham said: “We frankly admit that there have been incidents which have led to a plain perception of cosiness between particular senior MPS officers and particular journalists. The MPS also acknowledge that its decisions... not to reopen the phone hacking investigation were taken too quickly and with a defensive and closed mindset.”

In March, former commissioner Sir Paul Stephenson told the inquiry the Met developed a “fixed mindset and a defensive mindset” in 2009, during Yates’s review.

Garnham said today there was no evidence to suggest the force involved in a cover-up of phone hacking at News International, and said core participant victims had "conflated and confused" the perception and reality of relationships between officers and the press.

He added: “It’s right to acknowledge that the decisions were probably taken too quickly and with a defensive mindset that may not have asked the right questions. That was conceded by Sir Paul Stephenson and by others subsequent to him, and we respectfully urge you to adopt that.

“But there is absolutely nothing by way of hard evidence which calls into question the integrity of John Yates when he made those decisions. There’s nothing to show that he was in fact swayed in his decision-making by his friendship with [former News of the World deputy editor] Neil Wallis or his relationship with News International more generally.”

He told the inquiry claims DCS Phillip Williams, the officer who decided not to widen the 2006 investigation, had been influenced by "powerful media friends" were unfounded.