Planning applications in Harrow

Planning in Harrow

Harrow refuses more often than the areas we cover across almost every kind of project, and in a very even way. About 1 in 4 decided planning applications was refused, compared with about 1 in 7 across the areas we cover. Rear extensions, side extensions, front extensions and porches, garden rooms and outbuildings, and loft conversions and dormers were each refused about 1 in 4 times, so there is no obvious easy category to lean on.

The harshest corners are small. Fences, walls and gates and driveways and dropped kerbs were each refused about 1 in 3 times, the worst figures in the borough. Windows and doors, at about 1 in 5, are the one common kind of work that fares a little better than the rest, though still more than the national rate of about 1 in 9. Rear extensions are the biggest category, with more than 5,000 applications.

Harrow’s neighbours are mostly gentler. Barnet, Ealing and Hillingdon refuse about 1 in 5 and Hertsmere about 1 in 6, all less often than Harrow, while Brent, at about 1 in 4, is about the same.

The reasons given for refusal are consistent. Of the 2,697 recent refusals we read, about six in ten pointed to the size, bulk or design of the work, and about four in ten to the look of the street or area. Neighbours’ light, privacy or outlook featured in about three in ten, and not enough information being supplied in about one in seven. Highways came up in about one in eight. The practical lesson for a home extension is to keep it proportionate, in keeping with the street, and clear of neighbours’ windows, with complete drawings.

Householder decisions across 2023 to 2025 took a median of 8 weeks, and about seven in ten (69 per cent) were decided within 8 weeks.

Recent years have been a little easier. In 2025 about 1 in 5 decided applications was refused, against about 1 in 4 across the three years before. Application numbers fell to 1,989, from an average of about 2,565 a year, and the busiest year on record was 2022, with 3,392. Harrow has 27 conservation areas and 289 listed buildings.

Figures in this section as of 9 October 2026.