The Olympic Bill will be introduced to parliament tomorrow, only a week after London won the race to host the 2012 Games.

Work to deliver the world's biggest sports event has already begun, a special inquiry by the London Assembly into the 2012 Olympics heard yesterday.

The Assembly launched the inquiry to ensure that the London Games will be delivered on time an in budget, leaving a lasting legacy.

The second reading of the Olympic Bill would take place next Tuesday, Mike Lee, communications head of the London bid, told the hearing.

The Bill would set up the Olympic Delivery Authority (ODA), grant the Mayor of London powers to prepare for and stage the Games, and provide more legal protection for Olympic symbols.

The Olympic lottery, which will help fund the Games, will also be launched in the next few weeks.

The tender process for major Games contracts is starting. Contracts range from burying 13km (8 miles) of cable on the site of the Olympic complex and building the main stadium to providing toilet rolls and accreditation passes.

Large parts of the 500-acre site in Stratford also have to be decontaminated, as it previously housed a nuclear reactor.

About 80 per cent of the land is already in government hands, with acquisitions of the rest underway.

No-one has yet been forced to sell their land, Mr Lee said.

Asked about security costs of the Games, Mr Lee said £240 million have been set aside for that.

But the Athens Games in 2004 spent more than £800 million on security four times their budget.

Athens "started much more from scratch", while security was built into the designs of London's venues, Mr Lee insisted.

London will save £50 million in building costs of a temporary venue in Regent's Park after the IOC withdrew baseball and softball from the 2012 Games last Friday.

The other 26 summer sports will still be held.

With half of the 9.6 million tickets under £20, London had the lowest access prices of all five bid cities, Mr Lee added.

The Olympics itself would be run by the London Organising Committee of the Games (LOCOG). The body already exists as a company and will come into full operation this summer.

Most of the 50 members of the London bid team would stay on in the new body, Mr Lee said. London 2012 leader Lord Sebastian Coe will serve as chair and the bid's chief executive Keith Mills as deputy chair.

But the LOCOG's chief executive still has to be appointed.

The LOCOG will be accountable to the ODA, which will consist of members from national and London government as well as the British Olympic Association.

Once the ODA has been established by early next year, it would take over the task of awarding contracts in the run-up to the Games. At the moment it is done by the London Development Agency (LDA), the mayor's business arm.

"There is a huge task ahead," Mr Lee said. "But the opportunities for Londoners, for the rest of the country, are great."