A HACKER attack on MPs emails has raised fears of blackmail. A “sustained and determined” attempt to hack into the accounts of peers, MPs and their staff led to some of the UK Government’s internet network being disabled over the weekend.

The National Crime Agency and the National Cyber Security Centre are now investigating the attack after reports that hackers were selling the passwords of MPs and Cabinet ministers.

Tory MP Andrew Bridgen said a cyber attack could make people vulnerable to blackmail.

He added: “Constituents want to know the information they send to us is completely secure.”

International Trade Secretary Liam Fox said the attack, which began on Friday, was unsurprising in the light of the recent cyber attack on the NHS.

“We know that there are regular attacks by hackers attempting to get passwords,” he said. “We have seen reports in the last few days of even Cabinet ministers’ passwords being for sale online.

“We know that our public services are attacked so it is not at all surprising that there should be an attempt to hack into parliamentary emails.

“And it’s a warning to everybody, whether they are in Parliament or elsewhere, that they need to do everything possible to maintain their own cyber security, including having complex and therefore safer code words.”

Meanwhile Labour leader Jeremy Corbyn said it showed how vulnerable everyone was to cyber attacks, adding that more needed to be invested in cyber protection.

“It is a huge issue,” he said. “We all rely on computers, we all rely on emails, we all rely on digital records. You wouldn’t leave your building without importing documents under lock and key. A computer is just the same.”

An email to those hit by the attack said “unusual activity” had been seen and “closer investigation by our team confirmed that hackers were carrying out a sustained and determined attack on all parliamentary user accounts in an attempt to identify weak passwords”.

A parliamentary spokesperson said: “We have discovered unauthorised attempts to access accounts of parliamentary networks users and are investigating this ongoing incident, working closely with the National Cyber Security Centre.

“Parliament has robust measures in place to protect all of our accounts and systems, and we are taking the necessary steps to protect and secure our network.

“As a precaution we have temporarily restricted remote access to the network. As a result, some Members of Parliament and staff cannot access their email accounts outside of Westminster.

“IT services on the parliamentary estate are working normally. We will continue to keep members of both Houses of Parliament and the public updated as the situation develops.”

The spokesperson added that reports in the Sunday Times that MPs were not informed about the attack until 10.30pm on Friday was untrue.

“All users of the parliamentary computer network were alerted via email at 1.40pm on Friday, once it had become clear an attack was underway during the course of the morning and initial action had been taken to protect the network,” he said.

“Two further emails were sent during the course of that day, updating them on the attack, of which the 10.30pm email was the third.”