Behind the gleaming exterior of City Hall on the Southbank exists the powerhouse of London's political world.

It is from these corridors that the mechanisms which drive the capital, from the controversial Congestion Charge, to annual police budgets, are decided.

From the first moment you swish through the barricade of glass doors, it is clear millions have been pumped into the making City Hall a symbol of modern London.

A glass staircase leads from the very top - Boris Johnson's palatial office, painted a fetching shade of yellow, with views across the Tower Bridge - past the Labour and Conservative floors before plunging straight into a purple amphitheatre.

This open-top meeting room is where decisions are made, policies scrutinised, and Boris is grilled in his popular Mayor's question time.

What really goes on within this iconic mushroom, with its cutting edge architecture? What on earth do Boris and his fellow elected London Assembly (LA) members, who include Kensington and Chelsea councillor Victoria Borwick and former Westminster Council leader Sir Simon Milton, do?

Firstly, it is important to make clear that (like the building) the London mayoralty is a top-down organisation. Boris, and his team of advisers, make the decisions that matter.

He has general powers to do anything that will promote economic and social development, cultural life or environmental improvement in London. He also sets the budgets for four bodies in the Greater London Authority (GLA), the fire and police service, the London Development Agency and TfL.

The role of the 25 elected London Assembly members, who can only stand for four years, is to scrutinise the mayor.

They do not vote on policies, merely make sure that the right questions are asked to the right people.

From the City Hall café, where Boris is known to bellow across a packed lunchtime crowd for a takeaway, LA member Victoria Borwick (Cons) explained: "We have meetings with Boris's advisors every week. We make sure the top table is better informed. In turn, we take ideas back to boroughs."

However ambiguous the role may seem to be - and it seems that each member has implemented their own way of doing the job - do not underestimate their influence.

Assembly members, many of whom have a base in local politics, have the power to solve problems. For instance, Ms Borwick, who stood for London Mayor, has been able to thrust the Golborne Children's Centre, in Bevington Road, North Kensington, into the limelight by using it as a case study for the funding issues that such organisations face.

She has also organised a meeting between two leading figures of the Notting Hill Carnival, to help the under-fire festival.

Ms Borwick added that cross party assembly, in which the Conservatives form the minority, are not strongly whipped to conform with their political party - giving them greater freedom.

Information also feeds through the London Councils system, highlighting issues faced in borough's such as Hammersmith and Fulham and Westminster, to inform decision-makers.

And while the organisation is still a complicated melting pot of politics and bureaucratic policy, it is laudable that within the window-fronted offices no meetings can be secret.

The public is also able to view - both online or in person - any assembly meeting. City Hall's workings may not be as wellknown or well-understood as other political bodies.

But like the glass which coats its every surface, it is transparent.

For more information visit www.london.gov.uk