Garvan Walshe was National and International Security Policy Adviser to the Conservative Party until 2008.

Discovered in an archive of the Witanegemot of Mercia (c. 800AD). Translated from the Anglo-Saxon:

“In this age of Viking terrorism, our security is threatened by the advance of technology. As much as it is important to stimulate innovation, we have to be aware that it can be used for ill as well as good; fanaticism instead of progress.

“The fact is that new technologies, when used responsibly, can secure the company’s economic future, but those that manufacture them are too often so taken with the possibilities they offer that they do not realise how they can be exploited by criminals, and raiders.

“Once, this technology was only available to a few technically skilled experts and a small minority rich enough to employ them. But now it has advanced to the point that may be obtained cheaply, essentially for free.

“It has, of course, many legitimate uses. It can greatly improve the security of people’s private lives and business transactions. Used correctly, it is essential to commerce. But it has now become so widespread that the security services cannot keep track of all those who threaten our way of life, and who use its cover to plot murder and destruction.

“As Sir John Sawyers, former head of MI5 has said:

“We’ve never wanted to have no-go areas for the police in our communities but [totally private means of communication] would be creating no-go areas for evil doers of any sort online — terrorists, criminals, paedophiles — to carry out their business.”

“In a free society, you can’t have absolute security, and in a secure society, you can’t have totally unalloyed freedom. There has to be some compromise and you want to maximise them both.”

“The manufacturers have so far not behaved responsibly. They boast about strong defences and ‘unbreakable’ locks. But how are we to know these locks are not used to secure the progress of a plot to destroy a church or murder monks?

“Chubb and Yale, your time is up. If you do not provide the security services with a master key to every lock, and so allow the king’s men to enter the homes of suspected Vikings without them being alerted, we will ban your locks from Mercia.”

This is not, of course, how door locks are used. There is no central repository in which a copy of every door-key has been placed, and behind those locked doors, terrorists, criminals and paedophiles have plotted for centuries. But if the authorities need to go inside someone’s house to find a criminal or evidence of crime, they can go to a court and ask for a search warrant.

The same strategy can be used for messaging services like WhatsApp. Although they promise to encrypt messages at either end of the transmission, the company decrypts them on its server as well to analyse them and use them to sell information to advertisers. All the government needs to do is to require the messaging services to yield up information in response to an electronic search warrant as a condition of operating in the British market.

This will allow them to track those casual terrorists and criminals who are foolish enough to communicate on a public system. Serious terrorists will in any case avoid public networks. They’ll make their own. So-called encryption technology is simple applied mathematics (the most popular algorithms make use of properties of remainders, as in when in primary school you divided seven by two to give three with a remainder of one). It’s not terribly difficult for terrorists to write their own programs to do it. Computers are, by definition, general purpose machines. Even the web browser on which you’re reading this has a programming language called javascript that would be capable of being used for an encryption system of the “unbreakable” type the security services want to attempt to ban. Banning encryption technology makes about as much sense as banning kitchen knives.

The security services would do better to focus on cryptanalysis, and the building of machines specialised in decrypting particular communications, and the improvement of the spyware needed to observe the phones and computers of suspected criminals and terrorists. If the number of new threats has increased because of jihadists returning from Syria or elsewhere has increased, then they should have the resources they need. This won’t only keep people’s liberties intact, it will also be of use against serious terrorists.