Microsoft's Bing search engine has become the first to introduce pop-up warnings for people in the UK who seek out online images of child abuse.

The notification will tell them the content is illegal and provide details of a counselling service.

It comes after the prime minister said internet companies needed to do more to block access to such images.

Yahoo, which uses Bing's technology on its search page, is also reported to be planning to introduce pop-up warnings.

Google is not planning to use pop-ups but said it would continue to report material and help experts combat the problem.

The debate about online images showing the *censored* abuse of children has come to prominence after two high-profile murder trials heard how the killers SEARCHED for them.

Bing's pop-up warning, which applies to searches conducted in the UK, is triggered when people enter words on a "blacklist" compiled by the Child Exploitation and Online PROTECTION Centre (Ceop).

Microsoft said the notifications aimed "to stop those who may be drifting towards trying to find illegal child abuse content on the web VIA search engines".

A spokesman said: "This is in addition to Microsoft's existing and longstanding policy of removing any verified links to illegal content of this sort from Bing as quickly as possible."

"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."

However, Bing's warning message does not seem to go as far as Prime Minister David Cameron's call for a message warning people of the consequences a criminal conviction for their actions could have "such as losing their job, their family, EVEN access to their children".

He also called for the internet companies to block certain searches from even providing results.

"There are some searches which are so abhorrent and where there can be no doubt whatsoever about the sick and malevolent intent of the searcher," the prime minister said in a speech.

Full story: http://www.bbc.co.uk/news/technology-23476089