Microsoft is warning Brits who use its Bing search engine to hunt down child abuse content that they are attempting to view illegal material online.
The company debuted the pop-up message on Bing in the UK following pressure from the Prime Minister David Cameron, who has been pressing internet firms to do more to help prevent access to nasty images.
Microsoft said that the warning will appear when a search contains the phrases found on the Child Exploitation and Online Protection Centre's (CEOP) "blacklist".
A Redmond spokesman told the BBC that the pop-up, which also provides a link to counselling service Stopitnow.org, was introduced in addition to its policy of quickly killing verified links that connect to illegal content online.
"Microsoft has been, and remains, a strong proponent of proactive action in reasonable and scalable ways by the technology industry in the fight against technology-facilitated child exploitation. We have teams dedicated globally to abuse reporting on our services and the development of new innovations to combat child exploitation more broadly," he said.
In a speech at a children's charity last week, Cameron attempted to capitalise on the fact that the country's big four internet service provider's will all begin filtering content at the network level from the end of this year.
Smut and violence vs abuse images
It hasn't helped that the two separate issues of filtering what some subscribers might deem to be inappropriate content - such as pornography and violence - and the very different problem of illegal child abuse images found online have, to an extent, been conflated by Number 10.
Cameron couldn't resist talking about the "criminal challenge" (unlawful content) and the "cultural challenge" (for example: porn) of the two issues in the same speech.
What in fact has happened is that the telcos - BT, Virgin Media, BSkyB - have followed in the footsteps of TalkTalk's Homesafe system, which - as The Register first reported way back in 2010 - was built by Chinese vendor Huawei.
The reason for their decision to begin filtering content at the network level was a simple one: to avoid regulation. And the industry has argued that very little has changed - despite Cameron's strong-arming - since BSkyB, BT and Virgin Media agreed to make the switch over the course of the last few months.
In parallel, the PM has been asking search engines to make it harder for perverts to track down disgusting and illegal content that displays child sex abuse.
Yahoo! has already said that it too is considering a pop-up box like the one brought in by Microsoft.
Google has no plans to add such a warning to its search engine. But it recently threw cash at the problem by donating more than £2m to the Internet Watch Foundation - an organisation that roots out sexual abuse images found online and then reports them to Ceop.
Mountain View, Microsoft and other tech firms had previously donated tiny sums of money to the IWF, prior to political pressure being applied to internet players in the UK.
Last week Cameron told the likes of Yahoo!, Microsoft and Google that they had a "moral duty" to help stamp out illegal content on the web.
"If CEOP give you a blacklist of internet search terms, will you commit to stop offering up any returns on these searches?" he asked.
"If the answer is yes, good. If the answer is no and the progress is slow or non-existent, I can tell you we’re already looking at legislative options so that we can force action in this area."
Microsoft, at least, appears to be partially listening to the PM's warning, even if it's yet to outright block such material. ®