What Five Eyes does – and doesn’t – see

In the famous ‘Rainbow Portrait’ of Elizabeth I her gown is embroidered with eyes and ears, a reference to her efficient surveillance of the threats to the emerging nation state that was Tudor England. ‘Five Eyes’ is the modern equivalent of the concept but applied to the general security of the Anglosphere: the UK, the US, Canada, Australia and New Zealand. For an alliance that was originally one of listeners more than watchers, it might have been more correctly called ‘Five Ears’, but that name would hardly have conveyed its permanent vigilance.

The existence of Five Eyes owes more to historical accident than deliberate design – it could never be rebuilt

Thanks to the success of the Enigma operation, Britain emerged from the second world war persuaded of the importance of interception, signals intelligence (‘sigint’) and decryption. In 1946 the UKUSA treaty was signed (the secret text of which was not released until 2010), establishing a high degree of co-operation between Britain and America in the collection and analysis of sigint.

The alliance has proved to be durable and highly valuable. It combines the sophistication and expertise of the UK’s GCHQ with the large-scale capability of America’s National Security Agency (NSA). The degree of integration between the two intelligence organisations is unique given the sensitivity of their roles. Its strength means that over the years it has not been much affected by changing governments and administrations, and it is the keystone of the ‘Special Relationship’.

The arrangement was expanded to include Canada in 1948, and to Australia and New Zealand in 1956. The spread of Five Eyes from the Canadian Arctic to the Southern Oceans and beyond allowed it a vital collection capability during the Cold War. Its existence owes more to historical accident than deliberate design – it could never be rebuilt. And it is still strategically important today.