New national roaming Sim card connects to available networks so you are never without signal

Users can roam between all four major networks with Anywhere SIM to find the best signal

A new Sim card which automatically connects users to the UK mobile network that has the strongest signal where they are is set to go on sale in the next five weeks.

Anywhere SIM will allow users to roam between all four major networks in an effort to tackle poor reception in UK notspots.

The start-up company, based in Lancashire, has agreed a partnership with O2, which operates as the Sim’s “home” network, but also has contracts with EE, Three and Vodafone.

The Sim will look for the best 3G signal initially but regress to 2G if this is not available. At present, 4G is not currently covered by the service but the company say they will be working to add this feature in a year’s time. In addition, the firm will also be looking to widen their international coverage, which at present does not stretch beyond Europe, as well as looking to create pay monthly packages.

Current charges for Anywhere SIM's basic pay-as-you-go ”home“ service currently stand at 5p a minute for calls, 5p per SMS text and 5p per megabyte of data.

Founder Matthew Wright told the BBC that the Sim will appeal to “people who have experienced coverage issues. So, people who live in rural locations. And those who travel a lot and experience notspots - for example people that spend a lot of time in caravans and those who pursue outdoor pursuits - cyclers, runners, walkers, anglers, there's a long list that could benefit outside the big conurbations.“

There are limitations to the service, however. While mid-call the Sim cannot switch between networks meaning that if a notspot is encountered the call will end and contact can only be re-established later.

The basic service only lets consumers receive calls across all the networks, but dial-outs and data use is restricted to O2. Users will have to pay twice the price per call and per megabyte if they want to make calls and use the data across every network.

The basic service is also considerably more expensive than other alternative Sims. GiffGaff, for instance, offers 500 minutes of calls, one gigabyte of data and unlimited texts at a cost of £10 a month, but is limited to O2.

Anywhere SIM’s product comes in the wake of Business Secretary, Sajid Javid’s proposed “national roaming” plans, which call on the major mobile operators to invest a collective £5 billion to boost coverage across the UK.

The pay-as-you-go Sims will be sold via Anytime SIM’s website as well as on eBay and Amazon. The brand also has ambitions to team up with camping and farming groups whose members may benefit from the service.