Tony Blair has defended the Egyptian army's decision to remove Egypt's first elected leader - amid violent protests which have claimed more than 30 lives.
Supporters of ousted Islamist president Mohammed Morsi have vowed to fight until he is restored with little sign a peaceful resolution is on the cards.
Mr Blair said while he supported democracy, "efficacy is the challenge" and the Morsi administration had patently failed to deliver in its first year.
While 17 million people on the streets opposing the regime did not constitute an election, such an "awesome manifestation of power" would prompt the fall of a British government, albeit without military intervention.
The world must "engage" with the interim government to help it deliver badly-needed economic reforms because "we can't afford for Egypt to collapse", he warned in an article for The Observer.
And he said one positive to be emerging was that there was "open debate about the role of religion in politics" and "probably a majority for an intrinsically secular approach to government in the region".
"The events that led to the Egyptian army's removal of President Mohamed Morsi confronted the military with a simple choice: intervention or chaos," he wrote. "Seventeen million people on the streets are not the same as an election. But it as an awesome manifestation of power. The equivalent turnout in Britain would be around 13 million people.
"Just think about it for a moment. The army wouldn't intervene here, it is true. But the government wouldn't survive either."
He added: "I am a strong supporter of democracy. But democratic government doesn't on its own mean effective government. Today efficacy is the challenge. This is a sort of free democratic spirit that operates outside the convention of democracy that elections decide the government.," he said - noting that it was fuelled by social media.
"It is not always consistent or rational. A protest is not a policy, or a placard a programme for government. But if governments don't have a clear argument with which to rebut the protest, they're in trouble."