The House of Lords has upheld the secretary of state's decision in March 1993 to grant planning permission to the Manchester Ship Canal Company for the development of a sub-regional shopping centre at Dumplington, Manchester (Bolton Metropolitan District Council v Secretary of State for the Environment [1995] The Times, 25 May).The secretary of state's decision had been challenged by a consortium of eight Greater Manchester authorities.

The main ground of challenge was that the secretary of state had failed to take certain material considerations into account, that his decision was perverse and that he had failed to give proper and intelligible reasons for his decision.

The Court of Appeal had quashed the decision on the grounds that the secretary of state did not appear to have dealt properly with changes in policies and changes on the ground with regard to urban regeneration and the effect of the proposed development on existing shopping centres in Greater Manchester between the issue of his interim decision letter in August 1989 and his final decision letter in March 1993.Lord Slynn's judgment contains an important statement of the extent to which material considerations should be dealt with in decision letters:'What the secretary of state must do is to state his reasons in sufficient detail to enable the reader to know what conclusion he has reached on the "principal important controversial issues".

To require him to refer to every material consideration, however insignificant, and to deal with every argument, however peripheral, would be to impose an unjustifiable burden.'He casts doubt on Glidewell LJ's statement in the Court of Appeal, that where there is 'a failure to refer in a decision to a material consideration...the inference may be that the decision maker has not fully understood the materiality of the matter to the decision'.

Lord Slynn restricts the scope for drawing such inferences to where 'all other known facts and circumstances appear to point overwhelmingly' to a different decision.Applying this test, and in the light of references in the decision letter to s.54A and revised PPG6, he considered that it could not 'fairly be said that the secretary of state did not have regard to government policy current at the date of his decision, and to any changes which had taken place since 1988'.

With regard to changes on the ground in terms of the extent to which the predicted increase in retail expenditure had in fact come about and the extent to which it would be taken up by other permissions for retail development, Lord Slynn accepted that the secretary of state's 1989 assumptions had proved to be inaccurate.

He found the secretary of state to have been unclear in the way that he dealt with the changes in his 1993 decision but that he did not consider that the reasoning was so obscure as to be unintelligible.

He considered that the secretary of state's reason for not changing his view between 1989 and 1993 was that the original inspector had attached limited weight to his projection of retail spending.On the question of whether the decision was so clearly wrong that it ought to be characterised as 'perverse' and accordingly quashed, Lord Slynn f elt unable to agree with the conclusion reached by the Court of Appeal.

He considered that the secretary of state had a difficult decision to make but that this was essentially a matter for the secretary of state's planning judgment.When taken with the House of Lords' Witney decision (see [1995] Gazette, 28 June, 38), there are firm indications from the House of Lords that the courts should be extremely unwilling to interfere with planning decisions.In Bolton, the House of Lords has indicated that if a material consideration or argument is not referred to an inference may not necessarily be drawn that it has not been taken into account.In Witney, the House of Lords indicated that the weight which the secretary of state should attach to a material consideration is for the secretary of state to decide and is not challengeable by the courts.

So long as the secretary of state takes a material consideration into account, the weight that he attaches to the material consideration is almost entirely a matter for him.Both decisions make it increasingly difficult to challenge what is considered to be a 'wrong' decision by picking up deficiencies in the way in which particular issues have been dealt with, or perhaps not referred to.

Lord Slynn refers to 'a tension between the proper examination of all relevant material, and the need to come to some decision, sooner rather than later'.As well as reducing the scope for third party challenges of planning decisions, could this trend ultimately lead to shorter (and quicker) decisions? This, at least, would be universally welcomed.