Some Whitehall departments are saddled with more than 100 terabytes of legacy data, and are wasting time recreating old work at a cost of £500m per year, according to a Cabinet Office report.

The Better Information for Better Government report [PDF] said good information governance is critical for effective government.

However, it found: "There is an immediate need to improve the organisation and management of departments' accumulated digital records."

Over the next year the Cabinet Office, the National Archives and Government Digital Service intend to seek to drive change across departments and government as a whole while retaining a supportive, collaborative engagement model.

"Holding on to large volumes of digital material that has accumulated over time in an unstructured way poses a serious compliance risk," said the report.

"Unstructured legacy digital information also poses a potential operational risk to departments."

Access to searchable digital legacy information can also prevent civil servants recreating previous policy ideas that do not work or inventing new solutions that are not actually new, known as reinventing the wheel, it said.

"Estimates suggest that wasted effort recreating old work might cost government nearly £500m per year."

There are also likely to be opportunities for government if departments are able to harness the "big data" potential of their information.

The report noted the "significant volume of legacy information held by departments" – some have more than 100 terabytes of information within their systems, roughly equivalent to 1 billion emails.

It urged all government departments to evaluate the level of risk they face from legacy digital information collections and take appropriate action.

However, the Cabinet Office has previously been criticised by the National Audit Office for its failure to to co-ordinate the UK's government departments' efforts to protect their information.

The report slammed the government's "chaotic" approach to reporting personal data breaches, with 9,000 reported data breaches during 2015.

It said the government does not have access to robust expenditure and benefits data from departments. "The Cabinet Office has recently collected some data on security costs, though it believes that actual costs are 'several times' the reported figure of £300m," it said. ®