Control of space means control of the world. This controversial statement was made by Lyndon Johnson before he became US president. Echoes of this sentiment were heard this week when the head of China's air force said it was inevitable for the nation to build weapons in space. Whoever controlled it would gain military dominance, he said. Such talk will naturally revive fears of an arms race in space.

The comments by General Xu Qiliang are a significant departure from the stance usually adopted by the central government. Beijing has long insisted its space programme is peaceful. This enabled it to take the moral high ground when former US president George W. Bush announced in 2006 a new space policy that declared the country would preserve its freedom of action in space. That was generally taken to mean the US was free to deploy advanced weapon systems high up in the atmosphere or even in outer space. Proposals by Moscow and Beijing to impose a global ban on the use of weapons in space were rejected.

There was, of course, hypocrisy on all sides. In January 2007, China shot down an ageing weather satellite in a missile test. More than a year later, the Pentagon fired off a missile to destroy one of its spy satellites, claiming it was necessary to prevent a leaking tank from spreading toxic gas in the atmosphere. This month, a Nasa spacecraft blasted the moon with a missile. It said it was looking for hidden water but people can assume the data would be studied by the US military. Actions, in such instances, speak louder than words.