Less than half of London’s indoor space has proper mobile coverage
Key Points
- Only 46.6% of London’s measured indoor floor space had reliable mobile coverage
- Berlin reached 68.4% and New York reached 69.0%
- London’s indoor 5G coverage stood at just 42.7%
- Tall buildings and deprived boroughs had the weakest coverage
- Ofcom’s models put London’s indoor 4G coverage at over 98%
Only 46.6% of London’s measured indoor floor space had reliable mobile coverage in Q1 2026, compared with 68.4% in Berlin and 69.% in New York.
The Greater London Authority (GLA) and Ookla published the figures in their report A New Lens on the Connected Capital, using Ookla’s indoor signal scans from inside buildings.
The report counts floor space as “coverage-ready” when the median signal reaches -105 dBm or stronger and also meets a minimum signal quality threshold.
London’s gap widened further on 5G, where just 42.7% of indoor floor space met the threshold. Berlin reached 71.5% and New York reached 65.5%.
Tall buildings showed the weakest results in London. Across four quarters, 41.9% of observations in buildings with 13 or more floors were coverage-ready, against 52.5% in buildings with five to seven floors.
Berlin recorded 62.8% and 69.7% for the same building heights, a much smaller height penalty.
London’s 13-plus floor band contains 23.2 million square metres of measured floor space. Almost two-thirds of that space, roughly 15 million square metres, fell short of the coverage threshold.
The report put that figure at about 2,100 full-size football pitches of high-rise floor space.
More deprived London boroughs also tended to have weaker indoor coverage. Newham and Hackney scored lower than wealthier outer boroughs such as Richmond upon Thames and Hillingdon.
The weakest coverage also sits in London’s biggest employment centres. The five boroughs with the most poorly covered floor space hold 2.8 million workplace jobs between them, including Westminster, the City of London, Tower Hamlets, Camden and Southwark.
Ookla’s measured results differ sharply from Ofcom’s modelled figures. Ofcom puts London’s indoor 4G coverage at over 98%, while Ookla’s four-quarter borough average came to 44.5%.
The report explained that Ofcom models predicted signal at the outside of a building rather than signal quality inside it.
Ofcom named in-building connectivity as one of its four priority work areas for 2026/27 in its June 2026 discussion paper, Connectivity You Can Count On.
