Often, yes, and this is one of the most common misunderstandings we come across. Many owners assume listed building consent only applies to external changes, the front of the building, windows, the roof, but consent can be required for internal work too, sometimes for changes that seem minor.
When a building is listed, the listing covers the whole building, not just its exterior, and can include internal features specifically noted as part of what makes the building special: original staircases, decorative plasterwork, panelling, fireplaces, room layouts, even floor finishes in some cases. Removing or altering any of these can require consent, even if the change is entirely inside the building and invisible from the street.
Removing or altering an original staircase, fireplace, or decorative plasterwork almost always needs consent. Changing room layouts by removing or altering historic partition walls, particularly where they're original to the building, generally needs consent too. Even some services work, chasing extensively through decorative plaster ceilings for new wiring, for example, can require consent depending on the extent and what's affected.
Straightforward redecoration, repainting, and like for like repairs that don't alter or remove historic fabric generally don't need consent. The key distinction is usually between maintenance and repair (generally fine) versus alteration or removal of historic fabric (generally needing consent), though the line isn't always obvious, which is exactly why checking before starting work matters.
Grade I and Grade II* buildings are considered of exceptional or particular importance and tend to face closer scrutiny, sometimes extending to more features and a stricter interpretation of what constitutes a significant change. Grade II, the most common listing category, still requires consent for anything affecting the building's special interest, but the specific threshold can vary by local authority and by what exactly makes that particular building significant.
Unauthorised work to a listed building is a criminal offence, not just a planning breach. Local authorities can require unauthorised work to be reversed, at the owner's expense, and in serious cases prosecution is possible. This is one of the areas where getting advice before starting work, rather than after, genuinely matters, reversing completed work is far more disruptive and expensive than checking first.
The most reliable route is checking with your local authority's conservation officer before finalising plans, ideally with a clear description or drawings of what you're proposing. For anything beyond very minor changes, getting proper advice from someone experienced with listed building consent applications, rather than guessing, is worth the time it takes.
Removing an original fireplace surround to open up a room, even where the fireplace itself isn't used, is a common example of internal work that catches owners out. It seems like a purely internal, reversible decision, but if the fireplace is part of what the listing describes as significant, removing it without consent is a genuine breach, and reinstating an accurate replacement afterwards, if required, is far more expensive and difficult than getting consent (or being told the fireplace should stay) before starting.
For internal changes, applications generally need drawings showing existing and proposed layouts, a description of what's being altered or removed, and often a heritage statement explaining the significance of the affected feature and why the proposed change is (or isn't) harmful to it. For straightforward changes this can be a fairly light touch process; for anything affecting a feature specifically called out in the listing description, expect more detailed scrutiny.
