Prime Minister David Cameron has again waded into the debate about protecting kids from pornography online by personally stepping up pressure on ISPs to block smut websites by default.

His intervention comes during a torrid time for the Tories, with the party suffering heavy loses in local elections across the UK today.

The PM has also undergone plenty of haranguing from Labour MPs calling on the Conservative leader to sack his Secretary of State, Jeremy Hunt. Hunt has kept his job despite the resignation of one of his special advisers, Adam Smith, who apparently exchanged more than 100 emails with lobbyists at News Corp over Rupert Murdoch's bid to buy BSkyB.

Hunt, of course, is also the Cabinet minister responsible for overseeing the allocation of government funds to help upgrade the country's broadband infrastructure across most of Blighty.

According to a story in the Times this morning, Cameron is expected to consider whether telcos should cut off access to pornography and other adult material online "by default" for their broadband customers.

It's understood that Cameron will meet ISPs including Virgin Media and BT in the next few weeks.

In April, the industry lambasted an independent Parliamentary inquiry into online child safety by saying that its recommendations were unworkable.

At the time, the PM indicated his support for the proposals, which had been backed by the chair of the independent Parliamentary inquiry, Tory MP Claire Perry.

But telco trade outfit ISPA said that filtering such adult content at the network level and making customers opt in to allow them to access porn websites was a bad idea.

"It is easy to circumvent, reduces the degree of active interest and parental mediation and has clear implications for freedom of speech. Instead parents should choose how they restrict access to content, be it on the device or network level with the tools provided," ISPA secretary general Nicholas Lansman noted last month.

A Downing Street spokesman told the Times that No 10 was "consulting" on such a "default option" but added that "nothing" was "ruled in or out at the moment".

Privacy campaigner Nick Pickles of Big Brother Watch questioned the plausibility of such a system.

Web-blocking is a crude tool that does not prevent determined users accessing content. The broader consequences risk damaging legitimate businesses and undermining cyber security while further perpetuating the myth that this is an easy technological solution to a complex problem. Ultimately the risk is that ISPs will be expected to monitor everything their customers do online to ensure they are not doing something they should not be. Indeed, it is almost inevitable certain groups will call for this when web blocking is exposed as the ineffective and easily avoided instrument it is. Big Brother Watch believes the solution lies with greater device-level controls and law enforcement action aimed at those storing data or funding services that contravene the law. It would be unacceptable for the failure of technically naive policies to be used as justification for detailed monitoring of our internet use.

Earlier this week, ministerial plans to block supposedly unsavoury websites received something of a fillip, after a High Court judge ordered some of the country's biggest ISPs to cut off access to BitTorrent tracker site The Pirate Bay.

Sadly for Britain's lawmakers, anyone with an ounce of tech knowledge knows exactly how to evade such an online blockade – a fact seemingly lost on some politicians. ®