Brian Mawhinney, Secretary of State for Transport, will publish a report - never released by his predecessor, John MacGregor - which acknowledges that some new roads merely increase car usage. Dr Mawhinney will also announce how he intends to save about £200m from his roadbuilding budget. He is thought to be likely to axe, or at least delay, construction of the highly controversial Newbury by-pass. Campaigners against the by-pass say the Government may be in contravention of European directives if it proceeds with the project.
But Mr Mawhinney's acceptance of many of the arguments about roadbuilding put forward in the report by the Standing Advisory Committee on Trunk Road Assessment (Sactra) will be seen as confirmation that his department is keen to grasp a new, green agenda.
It confirms that the Tory party has finally rejected Baroness Thatcher's vision of the "great car economy".
Dr Mawhinney will announce that he intends to take account of the committee's findings to determine whether roads should or should not be built.
He also wants to commission new research to decide which roads create, rather than relieve, traffic problems. One theory is that orbital roads create bigger problems than others because they make journeys between new destinations feasible.
Previously the department has argued that new roads help absorb existing traffic and do not generate more motoring. It also emphasised the economic and wealth-generating effects of road construction.
Transport ministers have had the Sactra report since May, but Mr MacGregor, who was strong in his defence of the £2bn a year roadbuilding programme, delayed publication. The then roads minister, Robert Key, said that the report - compiled by departmentalofficials and external experts - would reach the public domain "in due course". That angered environmentalists who believed that the report presented vital evidence for public inquiries into road projects.
The findings have serious implications for the Government's cost benefit analysis formula for new roads, known as Coba.
Last week, sources indicated that Mr Mawhinney's acceptance of parts of Sactra's report casts even greater doubt over the widening scheme for London's M25 orbital motorway. The anticipated decision to scrap that project will not be announced this week because it was not scheduled to start in the forthcoming year.
Observers describe Dr Mawhinney as "relaxed" about the debate over roadbuilding, and point to a marked contrast in the atmosphere in his department since the departure of Mr MacGregor. Since then the old ministerial divisions within the department, whichleft one junior minister solely responsible for roads, have been broken down, and only one minister, Steven Norris, has survived in post.
These internal changes have been seen as another sign that Dr Mawhinney is anxious to change the traditional image of his department as the defenders of the formidable roads lobby. He and John Gummer, Secretary of State for the Environment, have been anxious to develop the Government's green credentials.
In a separate development, the RMT rail union confirmed that it was seeking legal advice about whether it can challenge the Government's proposed privatisation of Railtrack.
Labour frontbenchers and union officials believe that ministers may be proposing to act outside the powers given them in the Railways Act. The Act, which the Government says allows them to go ahead with the Railtrack sell-off, gives ministers sweeping powers but does not specifically mention Railtrack as opposed to British Rail.
A union spokesman said: "We have asked our solicitors to conduct an initial investigation. If there are areas which require a counsel's opinion they will come back to us."
Henry McLeish, Labour's rail spokesman, said: "I think it is a very serious situation in British politics when legislation is so vague but so powerful that a major union should be looking at the possibility of seeking a judicial review."
However, ministers say they are confident of their ability to proceed with the sale.Reuse content