The democratic gains made in the Arab Spring remain vulnerable to sectarian divisions, weak economies and the threat of counter-revolution, William Hague has warned.
In an interview with The Times, the Foreign Secretary said that the region faced "a lot of problems and even convulsions" in the years to come.
He expressed particular concern about the situation in Egypt, warning that a struggle for power in Cairo must not see the region's pivotal country slip backwards following the popular uprising which overthrew president Hosni Mubarak.
"The next few months could be quite turbulent and difficult in Egypt," he said. "It is perhaps the single most important piece of the jigsaw in the whole Arab Spring."
He said that the developments in the region which began earlier this year could now take a generation to work through.
"We mustn't expect each country to be neatly done in six months. It's not a computer game that comes to an end when you get bored. It's not a TV programme that finishes at 10pm. We are going to be working at this for the rest of our lives," he said.
Despite the problems, however, Mr Hague said that he remained "on the optimistic side", arguing the Arab peoples would not tolerate a return to authoritarian rule once they had tasted an alternative.
He said that President Bashar Assad of Syria, whose security forces have killed hundreds of civilians, should not count on being in power in six months.
"Events have shown that no one can assume they are able to carry on in power," he said.