Held, extension of time granted and claim allowed. (1) Section 284 of the Town and Country Planning Act 1990 on its ordinary wording did not debar a challenge to the planning permission which underlay the grant of a certificate of lawfulness of use or development and it was not an ouster provision, properly understood, so as to require a stricter construction. A cautious approach was to be taken when considering whether a statutory limitation on challenge, such as that given by section 284 to the certificate of lawfulness of use or development, ought to be extended to a different legal order, namely, the planning permission, which the statute did not protect. Allowing a challenge to the planning permission would not undermine the statutory purpose, since a certificate of lawfulness of use or development did not create absolute certainty of the lawfulness of the use going forward in any event and the statute envisaged that there might be a material change which removed the certified lawfulness. The effect of section 192(4) of the Town and Country Planning Act 1990 was that such a certificate established lawfulness on the particular date of the certificate but, where there was a subsequent change which altered the planning position in a material way before the relevant “use” was instituted, then the certificate might no longer operate to conclusively presume lawfulness. The “use” in question was that set out in the certificate, which, in the present case, was the stationing of caravans on the field which had not yet been instituted. The material change did not have to be a change on the land, such as a material change of use, but could include the quashing of an earlier planning permission. Moreover, the court retained a discretion not to quash a planning permission if, on the facts of the case, that was the appropriate response. Only in a highly unusual, if not exceptional, situation would the court quash a planning permission where the effect was to remove the benefit of an certificate of lawful use or development. It followed that the court had jurisdiction to consider the present challenge (paras 44–46, 49, 50, 54–58, 87).

(2) The same factors were relevant to the decision whether to extend time to bring the challenge, which was far outside the six-week time period for judicial review of decisions under the Planning Acts set out in CPR r 54.5(5), and whether to exercise the discretion not to grant relief. The present case was unique and exceptional because the factors on both sides of the balance were extreme. The starting point was that the extension of time sought, more than six years, was an exceptionally long time for such a challenge and for any judicial review. However, the reason for the delay was to be taken into account and that was, in part, because the impugned part of the permission, relating to the extension of the site, had still not been implemented because nobody had realised the effect of the permission for the first four years. That was a highly unusual situation and, indeed, a permission not implemented for that period of time would normally have lapsed. Thus, the first four years of the delay were justifiable. The reasons for the second period of delay, running from the date when the local authority had consulted on the owner’s application for the certificate of lawfulness of use or development to the date of the inspector’s decision granting such a certificate on appeal, were strong but not overwhelming. Although the claimant could have tried to judicially review the 2014 permission before the certificate was granted, it would have appeared quite unnecessary to do so and would have involved a convoluted legal position by the claimant of arguing the opposite of what its members were saying to the planning inspector. Although the best legal advice would have been to lodge a claim and then ask for it to be stayed, it was understandable why that might have been viewed as unnecessary and accordingly that second period of delay was reasonably justifiable, although it was still relevant to the overall balance. However, the claimant ought to have lodged a claim immediately after the certificate was granted and the period of delay thereafter had much less justification. The fact that it might well have received poor legal advice, and thought it appropriate to wait for the authority to decide whether or not to revoke or modify, was not a good reason for delay. That said, the prejudice to the owner from any reliance on the grant of planning permission, while real, was limited to the cost of the application for the certificate in respect of the field and the incidental costs, permission having subsequently been granted for the extension of the open period for the rest of the site. The prejudice from the loss of the 2014 permission itself was to be given little weight since that gain was itself unlawful and should never have been granted. Although there was some prejudice to good administration, the overriding factor was the harm that would flow from upholding the planning permission for a site in an area of outstanding national beauty in a highly prominent location, contrary to a host of local and national planning policies. The interests of the credibility of the planning system weighed heavily in favour of quashing the permission. Thus, striking a fair balance between the relevant factors, it was appropriate to extend time for bringing the claim and grant the relief sought (paras 31,59, 62, 73, 79–87).