Britain has developed online weapons and is prepared to strike first to defend the country's vital infrastructure against a cyber attack from an enemy state, the UK's Foreign Secretary William Hague has revealed.

According to Hague, the UK government is pouring hundreds of millions of pounds into beefing up the online defences as the country is facing the threat from a growing arms race in cyber space.

Hague told 'The Sun': "We will defend ourselves in every way we can, not only to deflect but to prevent attacks that we know are taking place. We are trying to prevent an arms race in cyber space.

"Given that the internet changes every day and billions more people will have access to it over the coming years, the potential for that arms race to grow and go out of control is enormous.

"There is no 100 per cent defence against this, just as there isn't against any other form of attack. We have to defend critical national infrastructure. We have to defend national security."

The Foreign Secretary added: "Of course we are very determined that such major attacks will not get through -- this is the reason for our heavy investment. But you now have to assume that they will be attempted."

The UK government is now pouring an extra 650 million pounds into developing deterrents to hostile viruses which are being produced almost constantly. The money is being split between the nation's eavesdropping spies and the Ministry of Defence which has set up a Defence Cyber Operations Group.

The move comes after a defence review ranked the threat of cyber attacks Tier One, the newspaper said.