The Liberal Democrats say they would put an extra £10 tax per ticket on internal flights in Britain to help fund improvements to the rail network (link below.)
http://www.rmtbristol.org.uk/2007/08/lib_dems_plan_air_tax_to_aid_r.html#more

They are also proposing to put a toll on road freight , while encouraging private investment in railways.

The party says it would generate £12bn in five years and be a temporary measure , without specifying how long.

"Plans to improve the railways must not be scuppered yet again by public spending constraints" - Chris Huhne , Lib Dem environment spokesman

So-called "lifeline" air routes , such as links between the Orkneys and Shetland and the mainland where travel options are limited , would not be taxed.

The flight charge would generate £150m a year , and the freight toll could raise £600m annually to be put in a "Future Transport Fund".

Private motorists would be spared in the near future , however, with Mr Huhne saying that a national road pricing scheme was not a practical option within the 10-year period in which experts say action must be taken to halt global warming.

The Future Transport Fund would be used for high-speed rail links connecting London with Birmingham , Leeds , Manchester , Tyneside and Scotland in the north and Bristol , Cardiff and Exeter in the west (link below.)
http://thisissomerset.co.uk/displayNode.jsp?nodeId=147472&command=displayContent&sourceNode=242195&contentPK=18005950&folderPk=113662&pNodeId=242222

It would be used to cut passenger fares; remove bottlenecks in the system at locations like Reading and Swindon; contribute to relief schemes like London's Crossrail; increase train lengths; and reopen some closed lines , such as the Oxford - Cambridge link.

One question :

Quote :

"The party says it would generate £12bn in five years and be a temporary measure , without specifying how long."

The lowest estimate that I have seen for a North - South High - Speed Link is £11bn. A study commisioned by the SRA , and conducted by Atkins , put the cost as high as £33bn (links below.)
http://www.rmtbristol.org.uk/2006/08/we_dont_need_the_200mph_rail_l.html

http://www.dft.gov.uk/pgr/rail/researchtech/research/highspeedlinestudysummaryreport

Wouldnt the cost of the North - South High - Speed Line alone use up (and probably exceed) £12 billion?