Are graduate recruiters illegally checking Facebook?

In recent polls, many recruiters have anonymously admitted that they would check a candidate's social networking pages before they came to interview - could this be illegal?
Companies could be infringing privacy if they dig up information about job applicants from social networking websites, internet expert John Carr has told The Guardian.

Carr, chairman of the UK Children's Charities' Coalition on Internet Safety, says that employers and education officials could be crossing the line when they look up information about applicants online. "It could be illegal - when the kids are posting a picture of a party, they are only doing it to let their mates look. They are not doing it for an application form," he said.

However, it remains unclear whether accessing people's private web pages or email accounts would constitute a breach of the law. What's your opinion? Do you expect to have your Facebook or Myspace screened before you go for a graduate job?