Hugh Pym BBC Business Correspondent

London's winning Olympic bid sparked wild celebrations

Exactly one year has passed since London won the right to host the 2012 Olympics.

So what has happened in that time? How much more of a reality is the British capital's games?

In terms of infrastructure there is very little to see. To be precise, there is one big hole in the ground.

The first major contract at the Games site near Stratford in east London began in April.

It involved dismantling pylons and taking overhead power lines underground. A 30 metre deep shaft has been excavated.

Tunnels bored out from there will carry high voltage cables. This is a complex job which could take eighteen months as much of east London's power supply runs across the site.

Demolition and clean-up work will begin above ground in the autumn.

The site itself has not been totally secured. Nearly nine per cent of the land required for the Olympic site and stadia has not yet been brought under the control of the Olympic Delivery Authority (ODA).

Many companies have been relocated and moved voluntarily, but about 200 businesses - most of them small firms - have yet to reach agreement.

Budget issues

A public enquiry, due to end in August, is hearing the case for compulsory purchase orders.

For the construction programme to run on time, vacant possession must be secured by the summer of next year.

Then there is the question of the budget. Government and ODA sources stick to the line that the original sums are realistic.

The total estimate for construction and infrastructure is set at �3.1bn.

This includes redevelopment work in the Lea Valley, funded by the taxpayer, which the Government says would have happened anyway whether or not London hosted the Games.

Lottery funding and London council taxpayers will share out most of the remaining bills.

Sceptics argue that the costs will inevitably over-run the original budget.

Work has begun slowly at the London 2012 Olympics Park

They point out that construction industry inflation in just one year has run way ahead of the assumptions made by Games planners.

Soaring energy and raw material prices will continue to put pressure on the financial budget.

Spiralling costs

The Culture Secretary Tessa Jowell has already conceded that security costs will be higher than first anticipated.

If the original budget is exceeded, it's not clear who will pick up the tab.

No cap has been put on the liability of council taxpayers. Their current contribution amounts to about �20 a year on a Band D property.

Over at the London Organising Committee ( LOCOG), the focus is longer term. It will inherit the stadia and facilities and run the Games in 2012.

The operating budget is set at �2bn - to be covered by corporate sponsorship, broadcasting rights and ticket sales.

The chief executive Paul Deighton is confident that this sum can be raised.

The search for sponsors from big business has begun, with a focus on banking, car manufacturers, telecoms and utilities.

But as yet no names have been announced. In the words of Lord Coe, chairman of LOCOG, "we have tried not to waste a single day".

Few would doubt that. There is no evidence that the London 2012 preparations are stalling.