London's most senior policeman has come under fresh pressure after the chairman of a group representing 24,000 officers said they had no confidence in him.
Sir Ian has been forced to defend his actions and comments
Peter Smyth, of the Metropolitan Police Constables Board, said a series of "embarrassing gaffes" by Commissioner Sir Ian Blair had undermined the force.
His comments were made at a Police Federation annual conference, attended by new police minister Liam Byrne.
Mr Byrne said the force had a track record of strong leadership.
Mr Smyth's speech, which fell short of calling for Sir Ian's resignation, asked the minister how he would restore public confidence in the commissioner.
He told the conference in Bournemouth: "On behalf of the 24,000 constables in London, and at the request of my branch board, I am telling you that we have no confidence in this commissioner."
Sir Ian has featured prominently in the headlines in recent months in a row over secretly-taped telephone calls with ministers, comments made about the Soham murders as well as remarks about the police shooting of innocent Brazilian Jean Charles de Menezes.
Within the force he has also met opposition for introducing community support officers, labelled by some officers as "plastic policemen".
Speaking later to BBC London, Mr Smyth said there were concerns police would be based in call centres while the streets would be patrolled by community support officers.
"We say that is wrong. We want police officers on the street, out in the community where people need them.
"There is a deepening discontent within my organisation and quite evidently among the wider public. We felt we could no longer stay silent on this issue."
During the conference, Mr Byrne responded to the criticisms, saying: "I think there's a strong track record of strong leadership within the Met Police.
"Now I have heard what you have said this morning, I will talk to the commissioner about it."
A spokesman for the Metropolitan Police said: "Most large organisations undergoing change risk being criticised by staff associations and the MPS is no exception."
He added that a new call centre would be staffed by police officers in the short term, with police staff filling most posts in the longer term.