'Right to be forgotten' would ensure users of Facebook and other sites could completely erase personal data

The European Union is to enshrine a "right to be forgotten online" to ensure that, among other things, prospective employers cannot find old Facebook party photos of someone wearing nothing but a lampshade.

In a speech to the European parliament, the EU justice commissioner, Viviane Reding, warned companies such as Facebook that: "A US-based social network company that has millions of active users in Europe needs to comply with EU rules."

In a package of proposals to be unveiled before the summer, the commissioner intends to force Facebook and other social networking sites to make high standards of data privacy the default setting and give control over data back to the user.

"I want to explicitly clarify that people shall have the right – and not only the possibility – to withdraw their consent to data processing," Reding said. "The burden of proof should be on data controllers – those who process your personal data. They must prove that they need to keep the data, rather than individuals having to prove that collecting their data is not necessary."

Under the proposals, national privacy watchdogs will be endowed with powers to investigate and launch legal proceedings against companies with services that target EU consumers.

Reding's spokesman, Matthew Newman, said: "A year ago she issued Facebook a warning because the privacy settings changed for the worse and now she's legislating to put flesh on those bones."

Facebook profiles have been accessible by default since January last year. Users have to opt in to ensure that their photographs and other information can be viewed only by friends.

Newman said companies "can't think they're exempt just because they have their servers in California or do their data processing in Bangalore. If they're targeting EU citizens, they will have to comply with the rules."

Privacy settings are often so complex that a typical user does not know how to use them, Reding's staff say. The new legislation will ensure privacy is inbuilt and not tacked on later as an added extra. The rules will also outlaw the surreptitious gathering of data without the user explicitly giving permission.

Newman said that the laws would make the EU the first jurisdiction to deliver a "right to be forgotten".

"Maybe you've been at a party, up until four in the morning and you or someone you know posts photos of you," he said. "Well, it's a harmless bit of fun, but being unable to erase this can threaten your job or access to future employment."

The rules would give consumers a specific right to withdraw their consent to sharing their data. "And after you have withdrawn your consent, there shouldn't even be a ghost of your data left in some server somewhere. It's your data and it should be gone for good," he said.

Facebook believes it is already compliant with EU law and says it is working alongside Brussels officials in the revision of data protection legislation that was enacted in 1995, in the early days of the internet.

"Facebook is fully engaged in the debates around the review of the European Union's data protection directive," said a company spokeswoman, Sophy Silver. "We work closely with data protection authorities across the EU and with the European commission and parliament..

Silver said Facebook users were already able to remove their data completely from view, after which it took a few weeks to clean up the company's servers.