What does “subservience” really mean in heritage decision-making?

In architectural and heritage conservation terms, "subservient" generally means that an extension should be secondary or subordinate to the original building. This can be interpreted through aspects such as scale, design, materials, and overall impact on the historic character of the building. Historic England's guidance (A Guide for Owners of Listed Buildings, Historic England, pg.12) advises that while there is no hard and fast rule to limit the size or scale of any extension, ‘a new extension should not dominate a historic building: this usually means it should be lower and smaller.’

But beyond that, there is no published definition of subservience in the NPPF or from Historic England, and case law has provided little clarity.

Some broad principles are fairly well established:

• An extension should be smaller in scale compared to the original building.
• It should complement, not compete with, the original architectural features.
• It should use materials and design elements that are sympathetic to the historic character.

The problem is that “subservience” is a sliding scale, not a fixed point. At what stage does a design stop being secondary and start competing with its host building? Such an undefined concept inevitably leads to subjectivity. And crucially, who gets to decide?

Conservation officers play an important role in safeguarding historic buildings, but their remit is not to impose a personal aesthetic. Their role is to assess harm against policy and guidance, weighing public benefit and proportionality. Yet too often, words like “subservient” or “appropriate” are used as catch-all – subjective judgements that can make it very difficult for applicants and their advisors to understand what will, or won’t, be acceptable.

When we looked at precedents nearby, there was a clear preference for flat-roofed “glass box” extensions, suggesting a favoured local approach. The clients had already been through three rounds of pre-application advice, each pushing them towards this direction. Perhaps because a box was easy to read as “subservient” — even if it didn’t truly reflect the character of the host building. This tendency risks stifling creativity and overlooking the value of well-considered contemporary design, which both Historic England and SPAB advocate. As SPAB notes: “new work should express modern needs in a modern language.”

Ultimately, it often comes down to a judgement on aesthetics — something the courts have recognised is inherently difficult to pin down. As Charles Mynors records, in Winchester CC v Secretary of State (1978) the judge observed:

“When one is dealing with questions of aesthetic value, I very much doubt whether experts are necessarily of any use at all… for every expert who said that something was exceptionally fine, one might quite easily find another who took the opposite view.”

In our Hampshire case, we felt the proposals clearly respected the thatched cottage, meeting the principles set out above, while allowing for a modest and carefully considered addition (by Tim Simmons of The Bazeley Partnership) that added to the building’s story rather than flattening it. The inspector agreed. But the process raised a wider question: how can heritage decision-making be made more transparent, consistent and evidence-based, while still allowing space for professional judgement? How can we be sure that judgement is balanced, fair and informed?

Do we need a shared, consistent language for ideas like “subservience,” or is subjectivity an unavoidable (even desirable) part of heritage decision-making? After all, no two historic buildings are the same, and sensitivity to context is vital.

One potential answer lies in design review. Design review has long been part of planning the built environment, from the ‘Committee of Taste’ in 1802 to the Commission for Architecture and the Built Environment in 1999, panels of experts have provided a collective view on the merits of design proposals. Today, regional Design Review Panels can offer a more rounded and impartial assessment, balancing different perspectives. But while these may work for large developments, they remain prohibitively expensive for small-scale or homeowner applications. Given current resourcing pressures on local authorities, it is hard to imagine a cost-effective model that could deliver the same for householders.

And yet, the principle is important: decisions reached collectively, with transparency and a plurality of views, feel fairer and more robust than those resting on a single, subjective opinion.

Perhaps this is the challenge we need to keep in sight: how do we preserve the necessary space for professional judgement in heritage decision-making, while also creating processes that give homeowners, designers, and communities greater clarity, fairness, and confidence in the outcome? “Subservience” may never be defined with absolute precision — but we can at least strive to make its application more consistent, balanced, and open.