Only a few months ago the Chinese government was aiming to put on “the best Olympics Games in history”. Now officials are talking in more cautious terms about a “safe Olympics”.

After a series of explosions and other potential security threats, Beijing is mounting one of the biggest-ever security operations for the games. The measures include surface-to-air missiles at the main stadiums and the deployment of 100,000 troops to deal with potential terrorist attacks. “Safety is our top concern,” said Xi Jinping, the vice-president, last week.