Sensitive personal data belonging to 500,000 job hunters have been exposed after hackers attacked The Guardian's Jobs website.

The website notified those affected via email on Saturday, calling the attack "a sophisticated and deliberate hack".

Names, email addresses, covering letters and CVs, were among the data exposed. However, the Guardian said some of the data was at least two years old.

"You have used the site to make one or more job applications and we believe your personal data, relating to those applications, may have been accessed. The supplier who runs the site has identified the manner in which it was hacked and taken steps to prevent a recurrence," the email read.

"We learned yesterday evening that the Guardian Jobs website has been targeted by a sophisticated and deliberate hack, which has breached the security of the data on the site," the website said.

The company revealed that it halted the attack part-way through and the site is now secure. It also said: "We have no reason to believe that any financial or bank data was compromised".

According to the website the hack was stopped before it was completed, and the site is now secure.

The Metropolitan Police's e-crime unit are now investigating the incident.

"The police remain anxious to keep information about the apparent theft to a minimum, in order not to compromise their investigations, but did agree with us that we could inform those users who may be affected," said a security notice on the website.

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