Face time: a billboard greets a citizen of Beijing. China will need to adapt from export-led growth to expanded domestic demand, a difficult political task to manage

It may take months to discover whether the actions taken by last week’s Group of 20 summit in London are enough to rescue the world economy from a prolonged recession, if not depression. The substance of its conclusions will have to convince capital markets, global financial institutions, investors and humble consumers that they can start to spend, borrow or lend again.