David Cameron fires warning shot at WhatsApp over use of encryption
In his speech, Cameron didn't mention the apps by name, nor did he explain how they or their makers might be affected, but the threat of control was a barely concealed theme all the same.
"In our country do we want to allow a means of communication between people which even in extremis with a signed warrant from the Home Secretary that we cannot read," he said. "My answer to that question is no we must not."
It seems unlikely that Cameron is suggesting that apps used by millions of UK citizens would be outlawed, as if such a thing would even be possible. His target is more likely the app makers themselves, especially Facebook's WhatsApp, which only weeks ago started using OWS's TextSecure end-to-end encryption technology on its Android version.
This gives the security services in the UK and beyond a technological headache because, the argument goes, it makes the job of state surveillance of criminal and terrorist suspects much harder if they migrate to such applications.
Future legislation could force firms to open their encryption technology to official inspection, something that on past evidence many would not feel comfortable doing.
This issue isn't unprecedented. In 2010, BlackBerry (then RIM) was forced to allow inspection by Governments such as Saudi Arabia and UAE that were unhappy about the cloak its server encryption had thrown over covert communications by criminals - threatened with shutdown in those countries BlackBerry made concessions without explaining what these were.
For the UK Government to go down the same path would be unprecedented, although both Cameron and Home Secretary Theresa May have already spoken of their intention to re-introduce in some form the draft communications data ('snooper's charter') bill blocked by the Liberal Democrats in 2013.
"We have a better system for safeguarding this very intrusive power than any other country I can think of," said Cameron of the potential dangers to personal freedom raised by such surveillance.
The Government will have been spurred on by MI5 chief Andrew Parker's call last week for new powers to combat extremism, with communications technology a primary battleground.
It's not hard to grasp why the Government is worried about WhatsApp and its ilk. Market leader WhatsApp recently revealed that it has 700 million active users, much of that replacing the declining medium of SMS texting. The future of messaging lies with this class of applications.
Critics will point out that although encryption is a big barrier, other surveillance techniques are open to the security services ranging from surveillance in the clear (hacking communications at endpoints) and exploiting software possible vulnerabilities in the apps themselves.