Transport Minister Andrew Adonis said: "Crossrail is the largest addition to the transport network in 50 years, and today's announcement that BAA have confirmed a £230M funding package for the project represents a major step towards its delivery. Business has long been a strong advocate for Crossrail and this is borne out today.
"Trains will run four times an hour for most of the day - cutting journey times across London and the South East and significantly improving rail access to Heathrow for thousands of passengers and airport workers every day.
"This is a hugely important scheme for the country. Its implementation will help to generate new jobs, and so support the economy, as well as assist the revitalisation of some of London's most deprived areas by offering them a fast and reliable connection to the rest of the city."
Adonis said Crossrail will generate 30,000 jobs and provide a £20 bn boost to the UK economy.
Mayor of London Boris Johnson said: "The agreement with BAA is very welcome news and underlines the commitment that businesses, as well as TfL and the Government, are showing towards delivering the funding package for Crossrail.
"This is another significant step forward in preparing for the construction of this landmark new railway. Works have already begun at Tottenham Court Road station and the contracts to design and build the multi-billion pound project are all on track to be awarded by spring 2009. All parties are committed to Crossrail's success, and together we will deliver it on time and on budget."
The Confederation of British Industry welcomed the news. Its deputy director-general John Cridland said: "This is a welcome and important step towards ensuring that this essential project is delivered. As well as giving the construction industry a significant boost at a difficult time, Crossrail will play a vital role in improving London’s transport network and enhancing its reputation as a world class city to do business in.
"With this major plank of funding in place from BAA, it is important that there are no further delays to Crossrail and that work begins as soon as possible," he said