Pressure is mounting on Metropolitan Police Commissioner Sir Ian Blair to resign over the shooting of innocent Brazilian Jean Charles de Menezes.
The force broke health and safety laws when officers pursued Mr Menezes to a Tube station and shot him seven times, mistaking him for a terror suspect.
Immediately after the verdict, Sir Ian announced he would remain in the job and was backed by the prime minister.
But Tories and Lib Dems said he should take responsibility for Met failures.
"It was a horrific series of mistakes and he is the person responsible," said shadow attorney-general Dominic Grieve.
He added that the whole incident was "rather shameful in terms of the competence of the police, that an innocent person should be shot in that fashion, when in fact there was a series of accidents that led up to it, which shouldn't have occurred".
Richard Barnes, leader of the London Assembly Conservatives, and a member of the Metropolitan Police Authority, said he would be pushing to have Sir Ian removed from his post.
"What we can do is have a special meeting of the police authority to discuss this, and I called for that meeting to be called within the next seven days.
"We can then take a vote of confidence if Sir Ian Blair does not accept his responsibilities."
A former senior Met officer, Brian Paddick, told BBC One's Question Time that Sir Ian was wrong to say he would not resign without first taking some time for reflection.
Meanwhile the family of Mr de Menezes in Brazil say the police must pay for their mistake.
The Brazilian was mistaken for a suicide bomber and shot at Stockwell tube station in 2005, the day after failed terror attacks in London.
Mr de Menezes's brother, Giovanni da Silva, told the BBC he was pleased with the outcome of the case but described it as just the start of the family's campaign for justice.
Sir Ian Blair has said he will not be considering his position
The Brazilian foreign ministry has offered to provide whatever support is needed by the family and said the way had been opened for further action.
During the trial, an Old Bailey jury heard that Scotland Yard commanders had made a string of errors on 22 July 2005 that culminated in an unwarranted risk to the public and ultimately the death of Mr de Menezes.
Mr Justice Henriques described it as "an isolated breach brought about by quite extraordinary circumstances".
"One person died and many others were placed in potential danger," he said.
Reports to come
Home Secretary Jacqui Smith dismissed the calls for Sir Ian's resignation, insisting he had her support, and Downing Street said Prime Minister Gordon Brown continued to have full confidence in Sir Ian.
After the verdict, the commissioner expressed his "deep regret" over the case but said he would continue to lead the Met.
Mayor of London Ken Livingstone said the health and safety verdict made it more difficult for police to protect the capital against terrorism.
He backed Sir Ian, describing him as "an incredibly talented officer" who had modernised and driven change through the Met, and had also brought down crime.
He added that the jury said the officer in command, Cressida Dick, bore no responsibility.
"So the idea that people farther up the food chain somehow bear that responsibility is nonsense."
A report into the shooting by the Independent Police Complaints Commission (IPCC) is expected soon and an inquest has also to take place.