It is no secret that the US and Britain collaborate closely on intelligence matters. Nor does any mystery surround the fact that their partnership is intense in the field of signals monitoring.
Ever since the heroic efforts of the codebreakers at Bletchley Park, Britain has an acknowledged expertise in this field. Treaties in force since the end of the second world war provide for large-scale data-sharing between Britain’s GCHQ and America’s National Security Administration – and also the intelligence agencies of Australia, Canada and New Zealand.
Fresh revelations from the cache of classified documents leaked by the US defector Edward Snowden contain revelations about this key intelligence relationship.