4G coverage in the rest of the UK is far below that found in London.

A report from mobile coverage company OpenSignal and consumer watchdog Which? found that people in Wales were only able to access 4G 35 per cent of the time, half as often as those in the capital.

4G coverage

The ‘State of the Mobile Network’ report said EE’s 4G network had the best availability with 64 per cent.

Vodafone was second on 60 per cent with 02 on an almost-identical 59.9 per cent.

3’s network only offered 4G 43.7 per cent of the time.

However 3 (24.4Mbps) was second to EE (27.9Mbps) in terms of average download speeds.

Vodafone was on 17.9Mbps and O2 on 16.1Mbps.

Average download speed

"It's clear mobile providers must do much more to improve their networks if they are to provide greater access to their customers," said Alex Neill, Which? managing director of home and legal.

Brendan Gill, co-founder of OpenSignal, said mobile data speeds were "consistently fast" but added: "Finding a 4G signal outside of London can still be a bit tricky."

Regulator Ofcom is building a crowd-sourced coverage map. People can assist it by downloading an app that automatically measures signal strength and data speeds.