The Government's bid to boost mobile coverage could easily backfire But the Government knows that there are votes to be had helping those folk still trapped in weak mobile areas. It has therefore launched a two-tier approach. It wants to spend £150m to finance hundreds of new mobile phone masts for the most rural areas; it would be better, of course, if subsidies were not needed but better an explicit transfer than a hidden one. Its second policy is far less defensible, however. It is considering new legislation to force providers to introduce network roaming across Britain, ensuring that customers automatically switch networks when they have no signal from their usual provider. In effect, people would hop networks in the same way they do when they travel overseas - minus the nasty price tag that is often attached. The Government will launch a consultation on the reforms this week after what it says is the failure of the big four operators - Vodafone, O2, EE and Three - to reach a voluntary agreement with ministers on improving coverage in areas where reception is patchy. In these so-called "partial not-spots," signal is limited to one or two mobile networks, rather than all of them. But the Government's answer isn't the right one, at least on the face of it, and the networks were right to refuse to play along. The incentives behind the idea are all wrong. For a start, it wouldn't solve anything in areas with no signal. No operator would have an incentive to be the first to extend their reach as others would simply be allowed to piggyback on their effort. That, of course, is the gist of the problem: compulsory intra-UK roaming would punish operators that have spent the most money investing in their networks, and help those that have spent the least money. EE, which has successfully pumped vast amounts of cash into its infrastructure over the past couple of years, thus gaining a key advantage in the cut-throat mobile market, would be especially unfairly treated. The devil is always in the detail with such ideas, of course. It could be possible to design a system whereby underperforming networks are severely penalised whenever their customers are forced to hop on to another network, with the fees handed over to the good network. Incentives to spend more would thus remain but the risk would be that customers would begin to look at all networks as interchangeable utilities, rather than as rivals competing on service quality and reach. The simple truth is that any heavy-handed intervention of that nature would be extremely dangerous and could easily backfire disastrously, reducing the investment in a crucial piece of the UK's infrastructure. The Government is right to be angered at mobile not-spots, but it must beware the law of unintended consequences.