IN AMERICA and Britain getting hold of a pre-paid mobile phone or SIM card (which gives a phone its number) requires little or no paperwork. For a small fee, customers can make calls, send texts and access the internet anonymously. Efforts to register users’ names and addresses have stalled. Privacy trumps claims that anonymous phones are tools of terror and crime.

Elsewhere, life is trickier. In China and India anonymous sales of phones and SIM cards are banned, though street vendors keen for a sale will sometimes waive the rules. In March five big Malaysian carriers were fined for selling phones to customers without checking their government IDs. In Africa and the Middle East a wave of new laws has caused bureaucratic bother over the past year, as millions queued to register their SIM cards or risk disconnection. Etisalat, the UAE’s biggest carrier, has disconnected 1.3m unregistered cards. Kenya has cut off at least 2.4m. From Afghanistan to Peru, governments are cracking down.

Uganda’s government says “terrorists, insurgents and enemies of the state hide behind untraceable phones.” UAE carriers, including Etisalat and du, claim the national registration scheme, “My Number, My Identity”, is a crime-busting project. Pakistan’s Ministry of Information says unregistered phones are used as remote bomb detonators, and for making fraudulent or annoying “obnoxious calls”. It wants to create a directory of mobile users.

But Oliver Leistert, an expert in the politics of mobiles at the Central European University in Budapest, says the schemes are often a thinly disguised form of social control. In countries that lack proper privacy laws, security agencies can on a whim track locations, or scan calls and text messages for key words suggesting dissent.

Kevin Donovan, a researcher at the University of Cape Town, says the schemes may criminalise the weakest. Poor people often lack government ID, or may be unable to travel to their nearest registration point. Mobiles are often shared.

Many carriers grumble at the huge task that governments are giving them. Pat Walshe, director of privacy at the GSMA, an industry club, says that little evidence exists of a link between registration and a drop in crime, but enforced logging will create a black market. Mr Donovan notes that someone determined to detonate a bomb or commit fraud can always use a phone obtained abroad.