Google Chrome starts telling users huge numbers of sites are 'not secure' after latest update

Many of the world's biggest websites now carry the warning

Sundar Pichai, new chief executive of Google, speaks at the company's Google I/O conference in 2012 (KIMIHIRO HOSHINO/AFP/GettyImages)

Millions of Chrome users are being warned that sites are "not secure" in an unnerving new change.

The tweak has been made in the latest version of Google's browser. It is intended as a way of encouraging sites to introduce the latest web technology – but means that large numbers of people are being told their browsing might be unsafe.

The warning applies to a whole variety of sites, including Mail Online, one of the biggest news sites in the world.

It is a consequence of Google's attempts to encourage sites to move over to HTTPS, a new secure way of delivering websites. Pages that use that standard have more encryption, making it harder for web browsing to be intercepted as it moves across the internet.

But HTTPS requires a major overhaul of websties – especially those with large infrastructures – meaning that many major websites have not yet updated.

Security experts warned that the message actually meant that the websites were less secure than others, not that they had become more compromised in any new way.

“As expected, several high-profile websites now greet Chrome users with a “Not Secure” warning from today," said Kevin Bocek, chief cybersecurity strategist at Venafi. "Understandably, this might create some confusion and concern – but people shouldn’t worry, it’s actually a sign that the internet as a whole is becoming more secure.

"The fact is, websites should be secure as the de facto standard; it’s only right that Google is warning against sites that do not use HTTPS attention so that users aren’t exposed to risk. This will pressure businesses to step up their game and improve security across the internet, which can only be a good thing.”

The messages have only just started arriving in Chrome with the release of the latest version of the software. Google has been warning about its arrival for months.

Google Chrome updates itself, meaning that the latest version of the software has probably arrived on your computer without you necessarily realising it.