While most landline numbers have been public information since Britain’s first telephone directory was published in 1880, the assumption has always been that mobile phones, which usually have one user rather than several, are more private.

Until now, mobile phone users have been able to choose carefully those to whom they give their number. So getting unwanted calls, whether from an unsolicited suitor or a salesman, will be a deeper invasion of privacy than when these calls are made over a landline.

Perhaps the most disturbing element of the new database is the risk it presents to children’s privacy. Although it is not intended that the database will make mobile phone numbers of those under 18 available even its operator accepts that many children’s numbers will be.

This is because many children’s phones are bought by parents, so some will be registered to the adults and thus it will be impossible to tell whether the number belongs to a child or an adult. Potentially, this could have very unpleasant consequences.

People have been taking their landlines ex-directory in their millions in recent years, as telemarketers become more and more intrusive and, rightly or wrongly, they become increasingly concerned about security. Against this backdrop, an outcry over this new database is almost guaranteed.

Still, mobile phones have a feature that most landlines still lack — a screen displaying the incoming caller’s number. If that number is withheld, or is not recognised, it will continue to ring only until the user sends it merrily on its way to voicemail, or rejects the call.

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