How do you change the Met's face?

There's a very telling moment in the BBC's landmark series on the Metropolitan Police, which begins on Monday on BBC One.

As teams of officers prepare for a street festival in Brixton, the south London suburb that is one of the hearts of black Britain, a commanding officer says the last image he wants to see that day is a cop in a confrontation with a black youth.

As the camera pans around the briefing room, there is a sea of white faces.

Given that London's population is incredibly diverse and drawn from all continents, the pictures on the television screen don't sit too well with the idea that the police are supposed to represent the society they are policing.

The five-part series The Met has been some 18 months in the making.

Four BBC teams were given open access to the force's units, other than counter-terrorism for security reasons and royal and diplomatic protection on privacy grounds.

Victor Olisa: Holding the line in Haringey

One of the most important characters in episode one is Ch Supt Victor Olisa, the borough commander for Haringey.

As an inquest jury decides that armed police lawfully shot dead Mark Duggan in 2011 - a death that triggered that year's riots - you can see his face drop as the dead man's family warn there will be no peace.

When he leaves the police station to talk to a growing and angry crowd, he is accused of being a stooge - a black man put in charge of a difficult problem just to stop black people complaining. In the video above you can see him being challenged by a journalist who questions whether he has the trust of Tottenham.

Meetings, meetings, meetings: The modern Met involves more than bashing in doors

Ch Supt Olisa says the organisation is at a crossroads - and this first episode of The Met tries to capture that tension: will the Met be able to transform itself into an organisation that commands the trust of all Londoners, rather than just some?

For decades, the Met was the career of choice for the capital's traditional white working-class communities.

But those types of officers in those numbers are representative of a city that has gone. While almost nine out of 10 of the force's officers are white - more than a third of the capital isn't. People born abroad (a different measure of ethnicity to skin colour) are in the majority in at least four of the capital's boroughs. Only 6% of the Met's senior officers, ranked inspector or above, are from a minority background.

As Northern Ireland knows to its cost, when a police force isn't drawn from all of the community it is empowered to police, sometimes with the use of force, trust is hard to come by.

The relationship between the Met and minorities in London reached rock bottom in 1999 when the damning Macpherson Inquiry into the murder of Stephen Lawrence branded the force institutionally racist.

Speaking at the launch of the BBC's series, the Met's commissioner, Sir Bernard Hogan-Howe, said that if people thought that the force was still institutionally racist, then he had to take that on the chin.

But while he says he is trying to change the culture of the force, he knows that he also has to change its face.

Scotland Yard has outsourced some of the stages of recruitment to ensure senior officers don't keep recruiting people who look the same as them. It has offered interest-free loans to help poorer applicants to complete a special pre-entry policing exam and, critically, introduced a London residency test.

Applications from minorities have gone up - not least thanks to a huge PR drive - and as these recruits enter the lower ranks, and older white officers retire, the force will move closer to representing what London looks like today.

But Sir Bernard says the Met cannot transform itself as quickly as London is continuing to change.

As the force's budget falls with forthcoming public spending cuts, the number of new officers the commissioner can recruit will correspondingly fall.

The Met cast list

In short, argues the commissioner, the Met needs exceptional help. He wants legislation for a one-off time-limited recruitment exercise that will force rapid change.

Such laws have had a dramatic effect on both the Police Service of Northern Ireland and the New York Police Department.

The system that Sir Bernard wants for London is simple. If an applicant passes the entry exams, they go into a recruitment pool. When there are the widest possible spectrum of candidates available in the pool, they all join the force at the same time.

In other words, there would be no exclusion of white applicants, simply a mechanism to ensure a better balance of new constables as posts become available.

The commissioner's proposals are backed by the London Assembly - but it's ultimately for the home secretary and Parliament to decide whether he gets what he wants.

The Met: Policing London begins at 21:00 BST on Monday on BBC One and is then available on the iPlayer.