By Alex Stevenson Follow @alex__stevenson
London is hosting the first international conference looking at the challenges - and threats - posed by cyberspace.
The development of cyberwarfare is of particular concern to those gathered in Britain - including China and Russia, viewed as the biggest threats to the west.
A "hostile state intelligence agency", believed to be China's, is thought to have sought to penetrate the Foreign Office's computer system earlier this week, underlining the extent of the threat faced.
"How to ensure we can all reap the benefits of a safe and secure cyberspace for generations to come is one of the greatest challenges we face," Mr Hague said.
"The response does not lie in the hands of any one government or country but it is too important to be left to chance.
"This needs to be a collective endeavour, involving all those who have a stake in cyberspace."
Mr Hague wants to establish international 'norms of acceptable behaviour' in cyberspace which falls short of a formal treaty.
These will develop into the 'London agenda', Mr Hague hopes, which will "help us realise the enormous potential cyberspace offers for a more prosperous, safe and open networked world".
The two-day conference will only address cybersecurity issues in one session, which will be closed to journalists.
The Stuxnet virus which set back Iran's nuclear programme and suspected data theft attempts against the International Monetary Fund are among the incidents which have attracted attention in the last 12 months.