This article is more than 8 years old

This article is more than 8 years old

Sweden has suffered its worst-ever data leak after an anonymous hacker hijacked the Twitter account of a prominent MP and released details of more than 90,000 private email accounts.

The hacker struck this week when he disclosed the passwords and email details of several Swedish political journalists. He tweeted them from the account of William Petzäll, a controversial 23-year-old far-right MP.

Petzäll denied having anything to do with the leak.

He pointed out that he has been receiving treatment for drug and alcohol addiction at a clinic in Sweden, after resigning last month from the anti-immigrant Sweden Democrats party.

The scandal deepened when it emerged the hacker had also raided the popular Swedish blog portal, Bloggtoppen.se.

He appears to have broken in several months ago – making off with more than 90,000 passwords and usernames.

These have also now been leaked, making it easy to hack the accounts of well-known politicians, editors and celebrities. The Aftonbladet newspaper also reported that another 57 websites have been compromised, potentially releasing the login details of up to 200,000 people.

The hacker's identity remains unknown. His online name is: sc3a5j.

In an interview with Expressen newspaper, he said he had masterminded the biggest internet breach in Sweden's history to remind people to change their passwords more often.

He said: "I dumped this information to let people know that they handle their information wrongly.

"Many web pages are not up to scratch. And consumers need to know they should never use the same [passwords] for different services on the web.

"This is how we got into Twitter accounts as well."

Expressen journalist Micke Ölander said on Thursday the affair wasn't an example of political skulduggery but was merely a wake-up call not to use the same password for all accounts.

"It's a story about the possible naivety of Swedish internet users who log into their bank account and the New York Times web pages using the same password," he said.