Two mega projects are on the drawing board in London - the east-west Crossrail underground link and a bid to host the 2012 Olympic Games.
This week we ask: Should Crossrail be linked with the Olympics?
Lynne Featherstone, Liberal Democrat member of the London Assembly
How can the government even consider hosting the Olympics without Crossrail? Every city that hosts the Olympics grasps the opportunity to build on their transport network with both hands. But not us.
If we show that we are not confident enough to build the Crossrail project on time and within budget, we will send the wrong message to the International Olympic Committee. We are hardly going to look like real players in the bidding war if we admit, before we even start, that we are incapable of successfully implementing a major piece of transport infrastructure for something as big as the Olympics.
And it is not as if London does not need Crossrail!
Arup has estimated 500,000 visitors will move in and around London to Olympic events. In all, 150,000 visitors will travel to the Olympic zone itself - 125,000 of whom will move through central London, placing a huge strain on the transport network. Current plans for transport improvements such as the Jubilee Line upgrade, Channel Tunnel Rail Link and extension of the Docklands Light Railway, do not cater for these visitors.
Linking the construction of Crossrail with the Olympics will ensure that the project does get built in the near future and not get delayed further.
Moreover, giving Londoners a new transport system means that they will get something in return for footing the bill for the Olympics, after 2012.
Coupled with the fact that the Office of the Deputy Prime Minister plans 293,500 new jobs in the Thames Gateway and 95,000 new house holds by 2016, new transport links are essential to relieve the strains on the London's tubes.
Peter Head, development director for transport strategy group London Regional Metro
Linking the delivery of Crossrail with just the chance of having the Olympics in London in 2012 will distort and disrupt the advanced planning stage that Crossrail has reached, and add a drop-dead deadline which adds cost.
Crossrail, particularly the core central cross London rail link, is an urgently needed sustainable development project. The first project milestone is commitment from government to go ahead with planning in a defined timescale. The decision to bid for the 2012 Olympic Games has added a significant set of additional milestones to the process.
The Games could proceed without Crossrail's extra east-west rail capacity, if Londoners changed their travel patterns for the duration of the event.
This is a sensible sustainable solution from the Games' funding point of view.
The real issue is whether London can win the Games on this basis.
To win, the government will have to demonstrate that it can deliver facilities in partnership with local authorities and the private sector, and that it has a clear direction on improving transport.
In this respect, Crossrail is the ideal vehicle.
If the government decides not go ahead with Crossrail now it will send all the wrong messages and damage London's chances of winning the Olympics because it will show a government unwilling to get on with key projects. Making a positive decision later will become more difficult because nobody will want construction going on across London during the Games.
If the proposed incremental approach is used, building the core east-west rail link first, the railway would relieve congestion, serve the Olympics and be delivered by the end of 2011.
Crossrail is a 50/50 joint venture company formed by the mayor's transport executive Transport for London and the Strategic Rail Authority to promote and develop two new rail routes through London.
Crossrail line one (Reading to East London) is designed to carry 40,000 passengers per hour with 24 trains running in central London.
Crossrail would be privately financed and cost £10bn to build, including a £3bn contingency.
Crossrail will submit its definitive business plan for an east-west London rail route this week, paving the way for parliament to draw up a hybrid bill giving the go ahead.
A decision on who will host the 2012 Olympics will be made in 2005.
London's chief competition is from Paris and New York.
London's Olympic bid will centre on the run-down Lower Lee Valley area of east London.