A planned high speed rail line between London and Birmingham can only be justified if the Government makes a firm commitment to extending it to the North, MPs have warned.

But they condemned the Government’s failure to publish even basic information about planned services to Leeds and Manchester – with just weeks go to before an expected announcement by Ministers that they are pressing ahead with the controversial £32 billion project.

The criticism came in a major report by the Commons Transport Committee, which has been seized on by both supporters and opponents of the high speed rail scheme known as High Speed Two or HS2.

MPs concluded that there was “a good case” for building the high speed line, and dismissed many of the arguments put forward by critics, including claims that growing demand for rail services could be met by yet more upgrades to existing rail lines.

But the support was lukewarm, and MPs made a number of criticisms of the Government’s plans.

In particular, the Committee demanded that the Government make a firm commitment in law to building the full “Y-shaped” network, which will run from London to Birmingham before splitting in two and continuing northwards to Leeds and Manchester.

Ministers will reveal the outcome of a consultation on HS2 in mid-December. If the Government decides to press ahead with the scheme, as expected, it will introduce a hybrid Bill to the Commons by 2013 allowing the London to Birmingham phase to be built.

But the Transport Committee insisted this Bill should also include a commitment to the second phase, involving the construction of lines to Manchester and Leeds by 2032.

In their report, the MPs said “We believe that there is a good case for proceeding with a high-speed rail network, principally because of the substantial improvements in capacity and connectivity that it would provide, not only for services to and from London but also between the major cities of the Midlands, the North and Scotland.

“There would also be substantial benefits to passengers and freight on the classic network from the released capacity that would result.”

But they also warned that the case for a high speed line “depends largely on the assumption that the full Y network will be completed”.

However, because the line will be built in two stages, with the London to Birmingham route constructed first, no detailed study of the planned northern section has been carried out.

The MPs said: “We recommend that no decision is taken until such strategic information on Phase II is published, appraised and consulted upon.”

Although not spelt out in the report, this would seem to be a demand for a major delay in the Government’s plans.

As things stand, Ministers are set to announce a final decision on the London to Birmingham link before Christmas, without the lengthy consultation on phase two – the lines to Leeds and Manchester – demanded by the Committee.

The MPs also criticised the Government for failing to publish a full transport strategy, warning that it was hard to evaluate whether or not high speed rail would succeed in promoting economic growth and bridging the north-south divide without seeing how it would fit in with other plans.

But in other sections of the report, the MPs stressed that it was essential to increase rail capacity – and dismissed so-called alternative proposals put forward by opponents of HS2.

Network Rail has claimed that the West Coast Main Line will be completely full by 2020.

In a blow for opponents of the scheme, the MPs warned: “Alternative proposals to upgrade the existing West Coast Main Line would provide additional capacity but, given the substantial recent growth in rail passenger numbers, it seems that the alternatives might prove inadequate.

“They do not offer the step-change or the wider benefits to passenger and freight that HS2 would do.”

But the MPs were also critical of the Government’s claims that HS2 would help the economy grow in the North and Midlands, and help reduce the north-south divide.

According to the Government, the first phase of HS2, from London to the West Midlands, would create 40,000 jobs—a potential 30,000 in “planned employment growth” around the high-speed rail stations (with two-thirds at Old Oak Common near London), 9,000 in construction of the line and 1,500 in the operation and maintenance of the trains.

Birmingham City Council claims HS2 services and a new station at Curzon Street will be a major catalyst for regeneration of the eastern part of Birmingham city centre.

The West Midlands Integrated Transport Authority (Centro) commissioned a study from KPMG which concluded that HS2, plus a programme of regional rail enhancements, would increase economy in the West Midlands by £1.5 billion, the equivalent of a £300 rise in average wages.

But the MPs warned that the economic benefits of HS2 would be concentrated around the stations.

“It seems clear that high-speed rail can have beneficial economic impacts in the areas immediately around the stations," they continued.

"The extent to which the benefits of high-speed rail might be felt over a broader area would seem to depend on the quality of local and regional transport networks and the extent to which the development of high-speed rail is integrated with wider economic development planning.

“The Centro / KPMG study of HS2, though positive overall, concluded that the benefits would be concentrated in central Birmingham and around the new Birmingham Interchange station.”

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