The UK and the US are to set up 'cyber cells' and conduct mock attacks on each other as part of a joint effort to increase defence against online threats.
A first staged attack is planned for later this year according to Downing Street, when the two intelligence agencies GCHQ and NSA will carry out a 'war game' aimed at the financial sector, involving the Bank of England and commercial banks in both the City of London and Wall Street.
The announcement was made by Prime Minister David Cameron ahead of his second meeting with US President Barack Obama at the White House.
The visit comes after a report released by the security and intelligence company GCHQ warned about the daily attacks by hackers, criminal gangs, commercial rivals and foreign intelligence services on companies’ computer networks.
The report also suggested that more than 80 per cent of large UK companies experienced some form of security breach last year. It estimates that incidents cost around £600,000 to £1.5m to fix.
"We have got hugely capable cyber defences, we have got the expertise and that is why we should combine as we are going to, set up cyber cells on both sides of the Atlantic to share information," Cameron told the BBC in an interview on Friday.
The "unprecedented" arrangement between the two countries is set to improve the information collection and it will also involve MI5 and the FBI. According to Cameron, big companies like Facebook and Google should cooperate more when it comes to monitoring location and communication between terror suspects.