The UK’s mobile 4G access varies wildly across the UK, with some of the biggest cities having the worst connections.
Middlesbrough was the best city for 4G access with 83% availability and Bournemouth was the worst at just 68%, according to a report comparing 20 of the largest cities.
London managed just 16th, above Nottingham, Cardiff, Southampton and Bournemouth.
Glasgow and Edinburgh were 9th and 10th respectively.
The average 4G availability across the UK is 65%, which means that users have access to 4G less than two-thirds of the time.
This puts the UK’s coverage at 54th in the world, behind behind Estonia and Peru.
The report by consumer group Which? and independent mobile coverage signal analyst OpenSignal also looked at average 4G download speeds, finding Stoke on Trent to be the fastest city and Brighton the slowest.
More than 500 million data readings were taken from the mobile phones of more than 30,000 users between the beginning of December and the end of February.
Alex Neill, Which? managing director of home products and services, said: “These latest findings underline the need for Ofcom to keep the pressure on mobile operators, so that every part of the country gets a decent service on their mobile phone.
“Our mobile phone is central to how we live our lives and that is why it is so frustrating when we can’t access emails or browse the internet on the go.”
OpenSignal chief executive Brendan Gill said: “The mobile data experience isn’t the same in every city for UK consumers.
“OpenSignal users found 4G signals more often in Middlesbrough than in Manchester and faster 4G connections in Stoke than in London.”
An Ofcom spokeswoman agreed that coverage needed to improve and that people needed “reliable” broadband, regardless of where they lived or worked.
She added: “Ofcom rules mean that virtually all UK premises must receive a 4G signal by the end of this year.
“We’re also making available valuable new airwaves to boost mobile broadband, and have challenged mobile operators to explore how to reach all remote areas and transport lines.”