text: The judge held that Mr Durkan acted unilaterally and unlawfully in authorising the Belfast Metropolitan Area Plan (BMAP) without securing consent from executive colleagues.
  His verdict came in a challenge to the SDLP environment minister's decision.
  It was brought by former enterprise minister Arlene Foster of the DUP.
  The judge backed claims that because its significance stretched across departmental responsibilities it needed approval from the Stormont cabinet.
  A decision on what remedy to grant in the case will be taken at a later date.
  BMAP identifies zones for retail, residential and commercial development across the city and outlying areas such as Carrickfergus, Lisburn, Newtownabbey and north Down.
  Among the most contentious aspects of the blueprint is a retail zoning which restricts future expansion at the Sprucefield shopping centre to bulky goods only.
  That would mean a long-proposed John Lewis store could not be built there.
  Mrs Foster, now the first minister, issued proceedings amid claims her colleague in the power-sharing administration breached the ministerial code.
  Mr Durkan had said efforts were made to get the issue on the agenda at executive meetings.
  During the hearing it was confirmed that the legal action involved a disagreement split down party political lines.
  The DUP is opposed to the restrictions adopted by the SDLP minister in BMAP, the judge was told.
  Counsel for Mrs Foster repeatedly argued that the planning framework was a cross-cutting, controversial matter which needed the agreement of the whole executive.
  He claimed "battle lines were well drawn" in the debate over allowing unrestricted retail development at Sprucefield, with the potential impact on town and city centre shopping.
  He alleged the environment minister was only interested in securing approval for his own pre-determined outcome.
  The judge was told seven of the other 10 Stormont departments were concerned enough about BMAP to want to take part in a special executive sub-group set up to deal with the issue.
  Mr Durkan's barrister contended that attempts were made to coerce him into ignoring his legal duties in dealing with the planning blueprint.
  He also claimed the environment minister was put under pressure by DUP ministerial colleagues over a policy which effectively blocked attempts to build a John Lewis store.
  However, the judge held that the decision did cut across responsibilities of others in the executive under the terms of the 1998 Northern Ireland Act.
  He confirmed: "It was therefore a function of the executive committee to discuss and agree upon it, rather than for the respondent to act unilaterally."
  In a statement following the ruling, the Department of Environment said: "DoE planning is carefully considering Mr Justice Treacy's full judgement and the outcome of today's decision."
target: Environment Minister Mark H Durkan had no legal power to approve a major new planning blueprint for greater Belfast, a High Court judge has ruled.