The transport secretary has been urged to approve the Crossrail scheme in London.

Business leaders from the Royal Institute of Chartered Surveyors, the CBI and the Corporation of London have joined forces to call on Alistair Darling to make a decision.

In the House of Lords on Monday, Lord McIntosh of Haringey, the government's deputy chief whip, said it was "better to get it right even if it takes a little longer".

Forum Response: Crossrail

A spokesman for Crossrail told ePolitix.com: "Efficient transport systems are the key to reducing travel congestion and disruption. Crossrail Line One represents one of the most important infrastructure developments for the capital and the UK as a whole.

"There are serious implications in not building Crossrail. Congestion on an already overcrowded system will worsen and conditions for passengers will suffer.

"There is also the potential that, faced with a failing transport infrastructure, international business may relocate to Europe, away from the UK altogether. Crossrail will play a key part in the Thames Gateway regeneration plans.

"Crossrail will establish a brand new network of services linking areas across London and beyond and allow existing suburban rail services to run through London.

"It will also reduce overcrowding on Underground lines as well as reducing congestion at a number of busy National Rail stations."Crossrail will provide a major boost to the development of London's integrated transport network and ensure that features such as full access for mobility impaired people are included as an integrated part of the design.

"By bringing about these improvements, Crossrail will make a significant contribution to tackling the problems facing the infrastructure of the South East."

Forum Response: Corporation of London

A spokesman for the Corporation of London told ePolitix.com: "London desperately needs Crossrail. Congestion and overcrowding are increasing year on year and London's future as an international capital city demands that this problem is tackled as soon as possible.

"Crossrail will bring a major increase in rail capacity, carrying an extra 150 million passengers a year, relieving congestion and offering greater access to employment opportunities right across the capital."

Forum Response: Royal Institute of Chartered Surveyors

Louis Armstrong, chief executive of RICS, said: "Along with many business and civic leaders RICS is growing alarmed at speculation in the press that the government may fail to give Crossrail the backing it needs.

"It is now thirteen years since this initiative was launched. Since that time the project has been subject to endless delays whilst London's infrastructure has deteriorated and the need for it has grown ever stronger.

"We realise that embarking on a project of this size and complexity needs very careful analysis but there is near unanimity that the business case for Crossrail is unassailable.

"We recognise that the range of transport infrastructure improvements in London that are needed cannot be funded exclusively through public taxation. In a newly published report, 'Funding London's transport needs', we set out some of the options for funding the gap.

"We believe that there is a growing consensus among the business and property communities on a number of possible ways forward. There is now a real opportunity to build on that consensus to create a genuine partnership between government and business on this issue. We would be happy to do all that we can to assist that process."

Forum Response: Institute of Directors

A spokesman for the IoD told ePolitix.com: "Crossrail is a vital infrastructure project for London. If the capital is to compete as a place for business then public transport has to improve. The government has to take the lead and back this major plan."