A review of public service data networks has heavily criticised many of them over their low levels of private information security.

According to the National Audit Office (NAO) report, more than one in three of the systems used by public services are not well enough protected against hackers or the risk of losing data accidentally.

Sir John Bourn, head of the NAO, said: "Good quality data is essential if performance measures and targets are to be used effectively to improve public sector delivery and accountability."

The NAO study checked up on the progress of these systems over the past three years - finding that while half passed inspection, a worryingly high eight per cent were "not fit for purpose".

Sir Bourn said that while "it is good news that data systems are improving" there are "lessons" for government departments to learn that should make influence their newer systems.

"If we are to have confidence in the performance reported by government, all systems used to monitor it must be robust," he said.