Concealed development first made headlines in 2011, when Robert Fidler built a mansion and hid it behind a wall of hay bales. Anna Russell outlines the current law around permission for development, including where there is concealment or deception

Historically, deception and concealment were no bar to achieving a lawful status for development. However, that position is now altered. Following important judgments and amendments to legislation, local planning authorities (LPAs) are now able to take enforcement action against unauthorised development that has been concealed, notwithstanding that the immunity period has passed.

In this article, I explain the concept of development, and the need for planning permission for any development, unless it has become lawful through the effluxion of time.


The LPA is concerned only with the development of land. Development is defined by section 55(1) of the Town and Country Planning Act 1990 (TCPA 1990) as being either an operational development (physical works) or a material (significant) change of use of land. If something is not development, it is not within the control of the LPA.

Development needs planning permission, which can be granted in one of two ways. Relatively minor types of development benefit from ‘deemed’ planning permission by virtue of the General Permitted Development Order 2015 (GPDO) – this is known as permitted development (PD). Express planning permission is required for all other development.

Development without planning permission constitutes a breach of a planning control, which the LPA can enforce against – unless the development has become lawful.

trees in a line


Lawful development

Development that has existed for a specified period of time, where no formal enforcement action has been taken in respect of it, becomes lawful and immune from future enforcement action. Section 171B of the TCPA 1990 provides different immunity periods for the two types of development.

In the case of operational development, no enforcement action may be taken after the end of a period of four years beginning with the date on which the operations were ‘substantially completed’. In practical terms, this means that, in the case of a building, the building is virtually finished and capable of occupation.

Where the breach is a material change of use of any building to use as a single dwelling house, no enforcement action may be taken after the end of a period of four years beginning with the date of the breach. The ‘four-year rule’ only applies if the building was previously used for something other than dwelling use – not if it was built as a dwelling and then lived in as a dwelling. That is because, in the latter instance, there would have been no material ‘change’ of use. Thus, in the case of a dwelling that has been erected for over four years but less than 10 years, the building itself becomes lawful and immune from enforcement action, but not the use of that building. In that instance, the building has a nil use – that is, it could be developed in due course, but would need planning permission. Whether permission is granted would depend on the planning merits and planning policy.

In the case of any other breach of planning control, which means any other material change of use, or breach of a planning condition, the period is 10 years; no enforcement action may be taken after the end of the period of 10 years beginning with the date of the breach.

These rules reflect the principle that if a development has gone unnoticed (that is, it has not resulted in a negative amenity impact) for a period of four / 10 years respectively, then that development is deemed not to be harmful to the amenity of the surrounding area, and should therefore be allowed to remain / continue.

Section 191 of the TCPA 1990 enables a person to apply to the LPA for a certificate of lawful development (CLD), which, if granted, is effectively the LPA recognising that the development has become lawful. In CLD applications, the onus is on the applicant to provide sufficient evidence to prove the lawfulness.


Historically, it was commonplace for an owner or occupier of land to deliberately conceal a breach of planning control, so that it accrued lawfulness. One example is the well-known case of Robert Fidler (Fidler v Secretary of State for Communities and Local Government [2011] EWCA Civ 1159), who secretly lived for four years in a mock-Tudor castle on his farm that he had deliberately constructed behind tall piles of hay bales, covered in tarpaulin, so that it was hidden from authorities. (Mr Fidler was ultimately forced by the courts to knock down the castle, after a long-running legal dispute with his LPA.) Such deliberate concealment was, until recent years, never considered to be a bar to lawfulness accruing; indeed, it was not uncommon for it to be recognised by LPAs and planning inspectors that a breach had been concealed, yet it did not affect the development benefitting from lawfulness.

The position changed in 2011 in the case of Welwyn Hatfield Borough Council v Secretary of State for Communities and Local Government [2011] 2 AC 304, in which the ‘Welwyn principle’ was established.

Case law: Welwyn

The landowner had planning permission to erect a barn for agricultural purposes. He built inside it a house, and lived there from 2002. In 2006, he applied for a CLD for residential use, which was refused. The planning inspector allowed his appeal. The LPA appealed to the High Court on a point of law, and argued that parliament could not have intended the obtaining of such permissions by deceit.

The LPA’s case ultimately succeeded in the Supreme Court. The landowner was found to have deliberately deceived the LPA; the deception used to disguise the use meant that the owner could not rely on section 171B of the TCPA 1990. (There was no requirement that such deception be of a criminal standard, only that it be deliberate.)

This case identifies four features that take a case outside the protection of section 171B(2) – this now constitutes the four-part test generally used to establish concealment.

  1. Positive deception took place in matters integral to the planning process.
  2. The deception was directly intended to undermine the planning process.
  3. The deception did undermine that process.
  4. The wrong-doer would profit directly from the deception if the normal limitation period were to enable them to resist enforcement (‘profit’ / benefit includes the avoidance of enforcement action).

So, even when development has been found to have accrued lawfulness (as a matter of fact), the LPA can argue the Welwyn principle to rebut the property owner’s asserted immunity from enforcement action. Thus, the development would otherwise have become lawful through the passage of time, had it not been deliberately concealed.

Case law: Jackson

In Jackson v Secretary of State for Communities and Local Government [2015] EWHC 20 (Admin), the allegation was a change of use from an agricultural barn to a mixed use as an agricultural storage barn and a self-contained unit of residential accommodation. An enforcement notice was served by the LPA, requiring: permanent cessation of residential use; removal of residential items; and restoration. The owner appealed the notice under section 174(2)(d) of the TCPA 1990 – that the use had become lawful through the effluxion of time. The LPA found that the use had become lawful as a matter of fact, but it opposed the lawfulness pursuant to the Welwyn principle.

The court applied the Welwyn principle, and the landowner lost the immunity that he would otherwise have benefited from through the passage of time.

The Jackson case was important because it held that not all four features of the Welwyn test are necessary to remove a case from section 171B(2); the four-parts to the Welwyn principle are sufficient to prove concealment, but not necessary. For example, in Fidler, no false representations were made during the planning consent process, yet deliberate concealment was still held to have taken place.

New legislation: planning enforcement orders

The Jackson case also considered whether new sections 171BA to 171BC of the TCPA 1990, introducing the planning enforcement order (PEO), replaced the law laid down by the Supreme Court in Welwyn.

Under the new legislative provisions brought in by the Localism Act 2011, an LPA can, if it suspects concealed development, apply to the magistrates’ court for a PEO.

On the evidence, a magistrates’ court may make a PEO in relation to an apparent breach of planning control only if –

a) it is satisfied, on the balance of probabilities, that the apparent breach has, or any of the matters constituting the apparent breach have, to any extent, been deliberately concealed; and

b) it considers it just to make the order, having regard to all the circumstances.

If a PEO is made, the LPA has six months in which to take enforcement action (to either serve an enforcement notice or a breach of condition notice).

It was held in Jackson that the legislative provisions for PEOs are not a replacement for the Welwyn principle, but are supplementary to it.

Looking ahead

Still at issue is determining which specific acts / omissions constitute concealment. There is already a plethora of case law on this point since the new laws came into force, and it will be interesting to see how the issue of concealment continues to develop in relation to lawful development.