EE has launched double-speed 4G on its high-speed network and introduced shared data plans for families and multiple device owners.

Double-speed 4G was turned on today (4th July) in 12 cities: Birmingham, Bristol, Cardiff, Derby, Edinburgh, Glasgow, Leeds, Liverpool, London, Manchester, Nottingham and Sheffield. More cities will be added in the future.

According to figures from EE, it will increase the current average speeds to 24-40Mbit/s, with a top-speed of 150Mbit/s. As the company pointed out, double-speed 4G isn't just about faster speeds for quicker downloads, but also about making more bandwidth available to all customers. It should ensure that no matter how many people are on the network, users won't see a slowdown.

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In terms of raw speed, though, double-speed 4G currently means that the UK will have a mobile network faster than those in the US and Japan, and equal to the best in South Korea.

We have an EE mobile contract and an iPhone 5 handset. To test the network speed we used the Speedtest app, which connects to the Speedtest.net servers. This automated test automatically finds the closest Speedtest server and runs a barrage of tests that find out what the Ping (latency), download speed and upload speed of your connection are. By turning off Wi-Fi and using the EE 4G network, we can test how fast our phone's connection is.

Before double-speed was turned on, the best we got from the network was around 20Mbit/s download. Testing today using the Speedtest app, we consistently got download speeds of around 37Mbit/s, with upload speeds hitting 20Mbit/s. That's a lot faster than your average broadband connection.

Double-speed 4G certainly seems to be working for us

"Our new double speed 4G technology means that we have the biggest, fastest and best network in the UK, and now the equal fastest in the world," said Olaf Swantee, CEO of EE.

All existing EE customers will be upgraded to double-speed 4G for free for the life of their contract. Any new customers will also get the double-speed network, too. However, this deal only lasts until September when we were told that EE would announce how it planned to charge for double-speed in the future.

Existing 4G phones, including the Samsung Galaxy S4 and iPhone 5 , will work with the double-speed network with no need for a software update.

In addition, the company introduced shared 4G plans. These are designed for families and multiple-device owners, so they can have one bill and one amount of data shared between everyone. First, a lead sharer signs up to a standard 4GEE phone plan; next, up to four friends, family members or devices can be added to the plan at any point. All phone users get unlimited calls and texts, but the data limit for the account is shared between all devices

It costs from £12 a month to add a phone and from £5 a month for tablet and laptops SIM only. If the sharers need a smartphone or broadband dongle, the prices start at £22 a month for phones and £11 a month for dongles. According to EE, as well as making things simpler, the shared 4G plans can also save money. Comparing a family of four using popular plans from other mobile networks, EE said a saving of £38 a month could be made.