In a recent high-profile planning decision, a Planning Inspector ordered the demolition of an unauthorised and “disproportionately large” sub-basement constructed beneath a Grade II listed townhouse in central London. The case highlights the critical importance of obtaining proper listed building consent before undertaking any works and the serious consequences of failing to do so.
Background
The property, No. 74 Park Street in Westminster, is a terraced townhouse dating back to around 1729. It has been Grade II listed since 1987. Consent was granted in 2010 for modest alterations to the first-floor terrace and existing basement.
However, the actual works went far beyond what was approved. A new sub-basement was excavated beneath the original basement, incorporating a gym, sauna, bathroom, cinema room, and storage. Additional unauthorised works were also carried out to the existing basement and other floors.
The Appeal
The property owner appealed the enforcement notice on several grounds, including:
• That the unauthorised works should be granted retrospective consent;
• That the steps required by the enforcement notice were excessive;
• That the compliance period was unreasonably short.
The Inspector dismissed most of these grounds. He found that:
• The leisure facilities in the sub-basement were not essential for residential use;
• The design and layout of the new level detracted from the building’s historic character;
• The harm could not be mitigated by sealing the space, it had to be removed entirely.
Importantly, while the sub-basement was not visible, the Inspector emphasised that its concealed nature did not lessen its impact on the building’s significance.
Other Works Considered
Other unauthorised works, such as modern partitions and inserted glass floor panels, were also assessed. While some features such as vented cupboard doors were allowed to remain, the Inspector took a strict approach overall.
For example:
• A modern partition wall was deemed unacceptable due to the loss of original panelling and cornicing;
• Glass floor lights, installed in the basement to illuminate the sub-basement, were not permitted due to their association with the unauthorised works.
Compliance and Costs
The Inspector extended the time for compliance from 12 to 16 months (short of the 24 months requested) and issued a partial award of costs against the appellant. A key factor was the appellant’s failure to consider earlier refusals of similar sub-basement proposals, which had already been dismissed on appeal constituting, in the Inspector’s view, unreasonable behaviour.
Our View
We are regularly instructed by homeowners and developers seeking to enhance listed buildings. This case is a timely reminder that engaging with your local planning authority and obtaining the necessary consents is not only advisable but essential. Unauthorised works can result in enforcement action, financial penalties, and irreversible reputational damage.
Early professional advice, along with open dialogue with conservation officers, can ensure that proposed works are both achievable and compliant.
If you are considering alterations to a listed building, please get in touch with our planning and heritage team. We’re here to help you navigate the process effectively and avoid costly missteps.
Ifath Nawaz
Planning, Development and Environment Lawyer
Tel: 020 3907 4017
Email: Ifath.nawaz@meum.group