Whitehall's computer systems are under threat from 1,000 deliberate cyber attacks each month – often from rival states – Britain's most senior technology ‘spook' has warned.

Iain Lobban, director of Government Communications Headquarters (GCHQ), last week told the International Institute for Strategic Studies that Britain's economy could be severely damaged by rising numbers of cyber threats to vital public computer infrastructure, such as IT systems supporting power stations and emergency services.