Microsoft's Bing the first search engine to comply with government demand for 'search term warning'

Bing box will warn users that the content they are searching for is illegal and tell them to seek counselling

Microsoft's Bing search engine has become the first in the UK to provide "pop-up warnings" to users apparently search for images of child abuse.

The pop-up will tell users that the content they are seeking is illegal and will provide details of a counselling service. The pop-up will only work on searches identified as made from the UK.

Yahoo, which uses Microsoft's technology for its search service, may also follow suit. Google, however, said that it was not planning to implement the notification but said that it would continue to work on finding and reporting the material

It follows a campaign by Prime Minister David Cameron to eradicate online pornography, which involves forcing internet service providers to provide a default-on censor to filter all pornography and, potentially, other material.

According to the BBC, Microsoft is working with the Child Exploitation and Online Protection Centre (CEOP) to filter its search results and to work out a list of search terms against which the pop-ups will be applied.

Cameron has demanded a meeting with representatives of the leading search terms in October to discuss progress towards blocking search terms included on CEOP's blacklist. It also intends to establish a transatlantic taskforce with the US to combat illegal and violent websites.

However, Microsoft's pop-up warning, while the first, does not go as far as the Prime Minister would like.

Cameron had called for the pop-up to warn that their action could lead to a criminal conviction and "losing their job, their family, even access to their children" - in a similar manner to current radio and television adverts against drink driving.