The Britain's Parliament was the target of a "sustained and determined" cyber attack on Saturday.
The attack attempted to identify weak email passwords.
The House of Commons said it was working with the National Cyber Security Centre to defend the network.
A spokeswoman for the House of Commons confirmed that unauthorized attempts had been made to access parliamentary accounts.
This attack comes on the heels of a ransomware worm that crippled parts of the country's health service last month.