The head of the Met has been backed by senior politicians

Who is meeting and why?

The authority is the watchdog that scrutinises the workings of Scotland Yard. It is made up of elected representatives and appointed members and is supposed to represent a cross-section of Londoners.

It meets monthly with the Met's chiefs to be updated on key issues from management matters to major crime-fighting successes. This special hearing is to consider the fall-out from the force's conviction over the Menezes shooting.

What happened at the trial?

The unprecedented prosecution of the Metropolitan Police at the Old Bailey led to it being found guilty of breaching health and safety law over the death of Mr de Menezes, who officers thought was a suicide bomber. The Met has been fined and has decided not to appeal against the verdict.

What was the reaction?

The Brazilian electrician's killing put public safety at risk

Metropolitan Police Commissioner Sir Ian Blair has come under enormous pressure to resign over the killing and the guilty verdict.

No single officer has faced prosecution over the death and critics say Sir Ian should take ultimate responsibility.

He says he accepts responsibility - but adds that there were no systemic failings in the Met that would warrant his resignation.

Did the matter end there?

The Independent Police Complaints Commission has produced two reports into the killing and how the Met handled the situation, which were both critical of the police. The IPCC's chairman Nick Hardwick has been personally critical of Sir Ian.

Has anyone actually asked him to resign?

Conservatives and Liberal Democrats in London have been leading a campaign to unseat the commissioner. The London Assembly has passed a vote of no confidence in Sir Ian - but because it has no oversight powers over the force that was largely an empty act.

So what can the MPA do?

The body has the power to hold a vote of no confidence and to then suspend or remove the commissioner, but only with the approval of the home secretary - or on her orders.

The procedure is not straightforward. Under the Police Act 1996, the MPA must give the commissioner an explanation in writing for their grounds - and they must allow him to make representations.

He has 14 days to decide whether to reply - and another 14 days to prepare his response. The main hearing then takes place. If at that stage the MPA still wants the commissioner to go, they must ask the home secretary for her final decision.

Does Sir Ian Blair have backing from the top?

On 7 November, during the Queen's Speech Debate, Home Secretary Jacqui Smith told MPs who have called for Sir Ian to go that they would never face the "split-second decisions" of police officers.

"We should consider soberly and seriously the impact that our statements have on such people," she said. "I believe that responsible politicians should back those who are protecting us against the terrorist threat."

Sir Ian is important to the government because he is at the forefront of modernising the force, introducing neighbourhood policing strategies and shaking up old-fashioned police culture.

But will that backing last?

Neither the prime minister nor the home secretary have shown any signs of withdrawing their support for Sir Ian and he also has the backing of senior police officers around the country.