The site and background
This case concerned a detached outbuilding at the front of a residential property at Worms Heath Cottages, Warlingham. The outbuilding had historically been converted from a garage and was physically separate from the main house, with its own access, kitchen and bathroom facilities.
The outbuilding had been occupied as a separate, self-contained dwelling for many years. Members of the same extended family lived in the main house and the outbuilding, but the two units functioned independently and were occupied by separate households.
The applicant sought a Certificate of Lawfulness for the existing use of the outbuilding as a separate dwelling. A previous application had been refused by the council, primarily on the basis that the evidence submitted was said to be insufficient to demonstrate continuous residential use over the required period.
The legal test
At the time the application was made, section 171B(2) of the Town and Country Planning Act 1990 provided that enforcement action could not be taken against the unauthorised change of use of a building to create a single dwellinghouse after a period of four years.
Section 191 of the Act allows an applicant to apply for a certificate to confirm that a use is lawful by reason of the passage of time. The relevant test is whether, on the balance of probabilities, the use has occurred continuously for the required period.
National Planning Practice Guidance makes clear that a certificate should be granted unless the local planning authority has evidence of its own, or evidence from others, that contradicts the applicant’s account or renders it improbable.
The evidence strategy
Following the earlier refusal, a comprehensive and carefully structured body of evidence was assembled to demonstrate continuous occupation of the outbuilding as a separate dwelling.
This included multiple statutory declarations from the current occupiers, from family members with direct knowledge of the occupation history, and from the neighbouring occupier at number 2 Worms Heath Cottages. The neighbour confirmed long-standing residential occupation and explained shared practical arrangements, including the use and maintenance of a shared septic tank, which supported the existence of separate households on the site.
Further corroborating evidence was provided in the form of historic utility and service records. These showed the installation of a separate telephone line and television services to the outbuilding in 2012, with accounts held in the occupier’s name and maintained continuously over many years. The timing of these connections aligned precisely with the dates given in the statutory declarations.
Additional documentary and photographic evidence was submitted, including dated photographs of the interior of the outbuilding and receipts for domestic appliances purchased and installed more than four years before the date of the application. These items remained in situ and were capable of being inspected by the council during a site visit.
Taken together, the evidence demonstrated not only occupation, but occupation as a fully self-contained home, separate from the main dwelling, over a continuous period well in excess of four years.
The council’s decision
The council granted the Certificate of Lawfulness in August 2022.
In issuing the certificate, the council confirmed that, based on the evidence provided, and in the absence of any evidence to the contrary, it was satisfied that the outbuilding had been used continuously as a C3 dwellinghouse for a period of four years or more. The council expressly relied on the balance of probabilities test in reaching its conclusion.
Why this case is significant
This case illustrates the importance of evidence quality and presentation in applications for certificates of lawfulness. The refusal of the earlier application did not turn on the reality of how the building was used, but on whether the council considered the evidence sufficiently clear, consistent and persuasive.
By assembling a coherent evidential narrative, supported by statutory declarations and independent documentary records that aligned in time and detail, it was possible to demonstrate that the legal test was met and that the council had no sound basis to withhold the certificate.
Although the time limits for immunity from enforcement have since changed, the underlying principles remain the same. Applications for certificates of lawfulness continue to succeed or fail on the strength, clarity and credibility of the evidence provided.
