One of the keys to Britain’s success has been its ability to harness the energy of a particular type: the institutional rebel. From Francis Drake onwards, characters who would be rejected outright – and most probably executed – by stiffer hierarchies instead lent British overseas efforts much of their vitality. There was an unspoken symbiosis to these relationships: these individuals gave the government what it wanted, provided the government gave them what they wanted. For many, this was simply an insatiable desire for adventure: and none more so than for Fitzroy Maclean, the author of Eastern Approaches

In the late 1930s, the British Embassy in Moscow was a diplomatic backwater.