When you don't need planning
The overwhelming majority of London kitchen renovations are internal works, classified as alterations rather than extensions or change of use, and therefore fall outside the planning permission regime entirely. You can rip out cabinets, change layout completely, replace flooring, add or remove internal walls (subject to Building Regulations), upgrade fixtures and finishes, install new appliances and any combination of those without needing planning permission. This applies to flats, houses, listed buildings (where listed-building consent rather than planning is the relevant control), and conservation areas (where Article 4 directions are aimed at external alterations not internal kitchen works).
When you do need planning
Three scenarios trigger a planning application even though the works are kitchen-focused. First, extending the kitchen externally: any rear, side return or wrap-around extension is a separate planning matter regardless of intended use, and most require either prior approval (permitted development larger home extension) or full planning permission. Second, structural changes to the external envelope, including replacing a window with bifold or French doors larger than the existing aperture in a conservation area, or adding a glazed lantern roof that increases overall height. Third, change of use — if the kitchen renovation is part of converting a single dwelling into multiple flats (each requiring its own kitchen and bathroom), the change of use requires full planning permission and Building Regulations approval as separate Class C3 dwellings.
Building Regulations always apply
Building Regulations apply to almost every London kitchen renovation regardless of planning status. Part P requires all electrical work to be done by a registered electrician (NICEIC or NAPIT-approved) and certified at completion; expect to receive an Electrical Installation Certificate covering the ring main, lighting circuits, cooker circuits and any new outlets. Gas work must be carried out and certified by a Gas Safe-registered engineer; expect a Gas Safety Certificate. Structural changes (wall removal under steel, additional load on existing joists from heavier kitchen appliances or worktops) require structural calculations and Building Control approval — Building Notice (informal, faster) or Full Plans application are both routes; cost £300-£800. Part F (ventilation) applies to any kitchen — mechanical extraction over the hob is required even where openable windows exist. Part L (energy) applies if heating system or boiler is being relocated or replaced.
