This project to upgrade this main London to Scotland route will be trimmed to such an extent that there are fears about how much of the work will go ahead.

Some work will begin in 2004-05 - at Allington in Lincolnshire - to help separate fast trains from slower trains crossing the main line.

Preliminary works will also be carried out to benefit capacity at the southern end of the route.

But plans to increase train frequencies, which could be carried out between 2005-10, are now "subject to affordability and further assessment of value for money".

The future funding will be determined after a wider study takes place.

This scheme - due to be completed by 2006 - has been put back two years after a revision caused when "projected costs had increased significantly".

London Mayor Ken Livingstone backed this scheme to provide east to west cross-London rail travel.

The SRA and the Transport for London body are preparing the business case for the project but no commitment has yet been forthcoming to finance the scheme, nor has any firm decision been taken on the exact route.

This �9.7bn upgrade on the London to Scotland route has already been much delayed, after the SRA announced the revised plan for the project last year.

The scheme is scheduled to be finished in its entirety by 2008 to making journey times between London, the Midlands, the north of England and Scotland much reduced as 125mph tilting trains operate on the line.

Power supply problems have thwarted the introduction of a number of trains due to replace the old slam-door rolling stock on southern England commuter routes.

The SRA is expected shortly to announce the award of a �1bn contract for a power supply upgrade which will enable the new trains to be introduced.

A feasibility study has suggested that new lines carrying 200mph trains could be better value for future building, than upgrading existing lines.

The study found that by 2016, major main lines will be running to full capacity.

The SRA is to consult on the conclusions of the study and said on Thursday that creating new lines for high-speed trains rivalling the French TGV version - could "bring significant wider benefits to the UK economy".

Plans to improve freight links between Southampton and the West Coast Main Line via the West Midlands and Reading have been reduced in scope.

A programme of resignalling and other infrastructure works to improve freight services between Felixstowe in Suffolk and Nuneaton in the West Midlands has also been deferred.

A further freight service improvement scheme - the TransPennine to South Humberside project - is also being deferred.

These are smaller schemes funded by the Rail Passenger Partnership scheme.

The SRA says that between 2003-05 there will be "very limited funds available" for any new schemes.

This is a north-south cross-London rail improvement scheme, designed to create better services and links for those travelling to and through London from both north and south of the capital.

The scheme had already faced delay - the project was due to commence this year but was put back a year. Now the work, which was due to finish in 2008, could be delayed even longer.

Not directly the result of price cuts, the delay has been prompted by the government's intervention.

It wants the rail authorities to come up with new proposals to counter what it believes are "serious deficiencies" in the Thameslink 2000 plans.