The Information Commissioner's Office (ICO) has criticised a proposed government plan to create a database of mobile phone and internet communications.

As part of the Communications Bill Internet Service Providers (ISPs) will be required to keep records of emails and internet phone conversations for a year by law – and the government is considering keeping the information centrally.

But the ICO says the plan could be a disproportionate response to the problem.

"Defeating crime and terrorism is of the utmost importance, but we are not aware of any pressing need to justify the government itself holding this sort of data," said Jonathan Bamford, assistant information commissioner.

"Holding large collections of data is always risky; the more data that is collected and stored, the bigger the problem when the data is lost, traded or stolen."

The plan is one of a few options being considered, according to the home office.