London's mobile data demand outstrips capacity

London areas with weak mobile phone signals have been highlighted in an interactive map released by City Hall.

The research, carried out by data firm Ookla tested 19 outdoor locations in nine inner London boroughs during weekday working hours and over the winter shopping period.

It found every area tested had slower network response times than regulator Ofcom's target of 50 milliseconds. Eversholt Street in Somers Town, Camden, and Dalston in Hackney were the worst areas tested.

It concluded that demand for mobile data was outstripping London's network capacity.

Suggested fixes for the problem require more masts, better fibre links and easier access to sites.

The tests measured download and upload speeds, response times and signal strength.

The report found Eversholt Street in Somers Town, Camden, and Dalston in Hackney failed all four categories, while Chapel Market in Islington, Brick Lane in Tower Hamlets and the area around Kings Cross Boulevard and Coal Drops Yard in Camden passed only one.

Phones connect to masts by radio waves, which weaken over distance and struggle to pass through buildings. Each mast can only serve so many people, meaning busy areas slow down at peak times.

The main fixes are more masts closer together - often small units fitted to lamp posts or bus shelters, and faster cables behind them to carry the data.

Mobile networks pay for and build this equipment, but they need somewhere to put it. Councils and landlords control many of the rooftops and street fixtures they use, and councils decide planning applications.

Mobile UK said London approved fewer than 40% of mast applications, against more than 80% in Greater Manchester, Leeds and Edinburgh.

London's skyline adds to the problem. New towers can block signal from existing masts, and the report found almost two-thirds of floor space in London buildings of 13 storeys or more lacked reliable indoor coverage.

Conservation areas and listed buildings restrict where visible equipment can go, with the report citing Brick Lane and King's Cross as examples.

Decisions are also split across 33 boroughs, so within each council, planning, highways, housing and property teams all make choices that affect masts.

Some deals to put equipment on street furniture give a single company exclusive access, which the report says can leave other networks at a disadvantage.

Pressure is growing and City Hall forecasts demand for mobile data in London will rise fourteenfold over the next decade, and that networks' current plans will not keep pace.

The recommendations call on councils to appoint a mobile connectivity lead, identify sites for new equipment, review rejected mast applications and consider signal coverage when approving developments.

City Hall said it would publish borough-level data, support councils, facilitate talks with networks and continue offering public sites for infrastructure.

Networks have been asked to improve coordination with councils, while the government is urged to treat poor urban mobile coverage as a distinct issue.

The measures are voluntary, carry no deadlines and come without additional funding.

All 10 fall to councils, even though City Hall said networks were responsible for investing in and running their networks.

Within the UK, London had the fastest response times of any major city and ranked fifth of 10 for download speeds.

Internationally, Ookla ranked London 17th of 19 cities for download speeds and last for upload speeds.

The report said the difference with the best-performing cities in the world lies in how their networks are organised and connected, not in how many masts they have.

In Sweden, two operators have shared a single network since 2009, pooling their money into fewer, better-placed sites. Denmark has had a similar arrangement since 2012.

Stockholm also has a shared fibre network under the city, owned by the city council, which gives every mast cheap, fast cables to carry data.

In London, networks buy those connections from competing private firms.

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