On the 22nd of January the Supreme Court unanimously rejected appeals brought by opponents to the HS2 project and others who object to the scheme as currently envisaged:-
R (on the application of Buckinghamshire County Council and others) (Appellants) v The Secretary of State for Transport (Respondent)  UKSC 3
R (on the application of Heathrow Hub Limited and another) (Appellants) v The Secretary of State for Transport and another (Respondents)  UKSC 3
The following is a brief synopsis of the issues considered by the Supreme Court.
The central issue was whether the Coalition Government was entitled to adopt HS2 as a key policy objective, and announce its intention to promote the scheme, without first conducting a full strategic environmental assessment pursuant to Directive 2001/42/EC on strategic environmental assessment (SEA Directive): http://ec.europa.eu/environment/eia/sea-legalcontext.htm. Such assessments are necessary in respect of large scale strategic land use plans which have far reaching effects on future land use policy in particular areas or regions. They accompany the requirements of Environmental Impact Assessment (also a requirement of EU Law) which focus on the localised impacts of individual projects: see Directive 2011/92/EU on environmental impact assessment (EIA Directive) http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2012:026:0001:0021:EN:PDF . The Government had announced its intention to go full steam ahead with the project in a command paper entitled , High Speed Rail: Investing in Britain’s Future: Decisions and Next Steps (Cm 8247, 10 January 2): http://www.official-documents.gov.uk/document/cm82/8247/8247.pdf . Did this document amount to a planning decision falling within the scope of the SEA Directive?
The SEA Directive is only engaged when the relevant government body adopts a plan or programme which is capable of legally influencing the body charged with granting development consent or fettering its discretion. For example, a decision to zone a particular area for a new garden city would have clear legal implications for the local planning authorities responsible for granting the actual planning consents. However, HS2 will be authorized by means of a Hybrid Bill procedure which is currently before Parliament which will make the final decision by approving the Bill or otherwise: for current progress of the Bill see http://services.parliament.uk/bills/2013-14/highspeedraillondonwestmidlands.html . The Supreme Court accepted the argument that, as Parliament is sovereign and cannot be made to bend to the will of the executive, the Command paper could not be construed as legally influencing the planning decision maker in the manner required by the SEA Directive.
This leads to the second major issue, namely, whether the environmental impact assessment, which will be conducted as part of the Hybrid Bill procedure, meets the public participation requirements under the EIA Directive. It was accepted that the Hybrid Bill procedure offers two channels of democratic oversight; namely, by virtue of the fact that the decision makers are democratically elected representatives and that the Committee procedure enables interested parties to voice their concerns or formally petition against the Bill.
The unanimous decision of 7 Justices of the Supreme Court is a ringing endorsement of the Hybrid Bill procedure as a means of authorizing major infrastructure projects of this scale. No doubt the Department of Transport will be mightily relieved by its decision to choose this procedure as opposed to the Planning Act 2008 or ministerial order under the Transport and Works Act (later it will be argued that these mechanisms may not have offered the same level of insulation from the SEA Directive). However, it raises some interesting issues regarding the relationship between the SEA Directive and the EIA Directive. In effect, a project of the magnitude of a long distance railway conflates strategic planning issues with the specific planning issues raised by the scheme itself. In one sense it is a single project, but it is a project which encapsulates a multitude of strategic considerations of national importance. As a result, it is difficult to divide the planning decision into the two step process upon which the separate SEA and EIA Directives appear to be predicated. The Hybrid Bill procedure further serves to conflate consideration of the strategic elements of the scheme and the specific and localized environmental impacts on the ground. This is because it will fall to Parliament to consider both the localized effects of the scheme and the wider strategic ramifications. Moreover, Parliament’s hand are not tied by a strong steer from a higher authority regarding how the individual scheme should fit into the wider planning picture.
A Bill of another type, namely the private Bill, was instrumental in the development of the existing railway system. HS1, Crossrail and now HS2 have established that an Act of Parliament will remain the most effective means of authorizing major rail building projects in the future.