Authorities in the United Kingdom have fined Sony £250,000 ($396,000) for a widespread 2011 PlayStation Network data breach — a breach that the government says "could have been prevented." Describing the incident as a "serious breach of the Data Protection Act," the country's Information Commissioner's Office (ICO) criticized Sony's European branch for not doing more to strengthen the security of its gaming network.

The April 2011 hack shut down Sony's PSN for several weeks, after exposing the personal data of about 100 million accounts. Company officials publicly apologized for the breach in May of that year, offering free games to all PSN users, but the ICO on Thursday said Sony's infrastructure should have been strong enough to defend against the hack in the first place.

"Simply not good enough."

"If you are responsible for so many payment card details and log-in details then keeping that personal data secure has to be your priority," ICO deputy commissioner David Smith said. "In this case that just didn't happen, and when the database was targeted - albeit in a determined criminal attack - the security measures in place were simply not good enough."

For its part, Sony says it has taken concrete measures to reinforce security in the wake of last year's incident. The ICO, meanwhile, said its fine was determined according to the severity of the breach, calling it the most egregious it has ever seen.

"There's no disguising that this is a business that should have known better," Smith said. "It is a company that trades on its technical expertise, and there's no doubt in my mind that they had access to both the technical knowledge and the resources to keep this information safe."

In October 2012, a California judge threw out most of the claims in a class-action suit brought against Sony, ruling that the company's PSN breach did not violate consumer protection laws.

Update: In a statement provided to The Next Web, Sony said it plans to appeal the ICO's decision:

Sony Computer Entertainment Europe strongly disagrees with the ICO’s ruling and is planning an appeal.

SCEE notes, however, that the ICO recognises Sony was the victim of “a focused and determined criminal attack,” that “there is no evidence that encrypted payment card details were accessed,” and that “personal data is unlikely to have been used for fraudulent purposes” following the attack on the PlayStation Network.

Criminal attacks on electronic networks are a real and growing aspect of 21st century life and Sony continually works to strengthen our systems, building in multiple layers of defence and working to make our networks safe, secure and resilient. The reliability of our network services and the security of our consumers’ information are of the utmost importance to us, and we are appreciative that our network services are used by even more people around the world today than at the time of the criminal attack.