The Chinese can be forgiven for seeking out a reliable ally on their border. With Russia to the north, rival India to the south, an increasingly defiant North Korea to the east and Afghanistan in the throes of turmoil to the west, good neighbours are in short supply. That Pakistan comes closest to what the Chinese like to call an “all weather friend” shows how poor China’s options are.

It is an odd relationship that has been decades in the making. China is consolidating it with billions of dollars in infrastructure and energy investment, military exports and bailout loans to prop up the Pakistani currency. The latter have been worth $1.2bn since last year, underlining the extent to which Islamabad is becoming reliant on Beijing as US patronage wavers. This alliance presents risks for both sides. Meanwhile, the west cannot afford to abandon nuclear-armed Pakistan altogether, as much as it might like to.

On the surface the two states have little in common. The Chinese state is strong and its economy is growing. The Pakistani state, apart from the military, is weak and its economic performance disastrous. China is communist and religion is tightly controlled. Pakistan is Islamic and religious fervour is everywhere.