Darling is to present the CSR to the House at 3.30pm today, alongside his Pre-budget report. Darling is also expected to release the Government's response to last year's Eddington study into Britain's future transport needs.
The CSR is widely expected to to hit public spending hard, and transport spending a particular target. Yet transport has been listed with health and education as a priority by prime minister Gordon Brown and is seen as important to the economy.
Last year's report by Sir Rod Eddington underlined this and proposed road pricing, investment in city transport and support for international "gateways" of airports and ports, as well as planning reforms to cut delays in building them.
The Department for Transport is planning a transport strategy document which will be a response to the Eddington report, but taking account of Sir Nicholas Stern’s report on climate change economics.
The CSR is promising a a 10 year spending profile for transport; the last spending review had this and the Treasury has said previously that it would continue this because of the need for long term certainty.
Excluded from this is rail spending. This has already been decided with a Rail White Paper and "High Level Output Specification" in the summer, setting out what the Government wants the railways to do over the next five years.
This included 1300 extra carriages and the go-ahead for the Thameslink scheme in London and the rebuilding of Birmingham New Street and Reading stations, as well as a "strategic freight network". The Government has also just given the go-ahead for the Crossrail scheme.
One area under particular threat is the upgrade of the Tube. The London transport budget has been messed up by the collapse of the underground PPP contractor Metronet, and reports have suggested that the Treasury have been threatening that Crossrail's go-ahead means that the Tube upgrade should now be stopped altogether.