Foreign Secretary William Hague has called on the international community to offer financial backing to democracy movements in the Middle East.
Speaking at the Lord Mayor of London's Easter banquet in the Mansion House, Mr Hague said the support would help prevent the so-called Arab Spring collapsing back into "more authoritarian regimes, conflict and increased terrorism".
He urged the European Union to offer the "hand of friendship" to nations such as Tunisia and Egypt on its southern borders, suggesting that a free-trade area and then a customs union could be possible in the future.
"All of this must should be accompanied by our partners achieving clear and sustainable political and economic reform," he said.
Sky's security editor Sam Kiley said the Foreign Secretary's remarks were "a big boost" for the pro-democracy groups in the region.
"This is an absolutely extraordinary promise to make ... he is offering to the countries of North Africa and the Near East the opportunity, effectively in economic terms, to join the European Union," he said.
Addressing Libya and Syria, Mr Hague warned that their atempts to crush the popular uprisings in their country were "doomed to failure".
"Simply refusing to address legitimate grievances or attempting to stamp them out will fail. The idea of freedom cannot be confined behind bars, however strong the lock."
He said Britain was seeking UN condemnation of Syrian President Bashar al Assad's use of the army to crack down on dissent and with the EU to sanction those involved in the violence.
Mr Hague said the eruption of pro-democracy movements in the Middle East and North Africa was "the most important development of the early 21st century".
He predicted that the "Arab Spring" would sweep across the globe and could lead to "the greatest advance for human rights and freedom since the end of the Cold War".
Mr Hague made the speech ahead of a meeting of countries involved in Nato's campaign in Libya at which delegates were expected to discuss financial aid to the rebels.