New analysis revealed eight new luxury houses have been built in the Ch'angkwangsan Compound, a secretive estate at the heart of Pyongyang. 'The most significant activity occurred about ten years ago when South Korean forces simulated such an attack – and it sent Pyongyang into a tizzy.'

'Sometimes it involves early morning travel, underground facilities or decoy motorcades. 

Mr. Madden said: 'These new residences are located in the heart of Pyongyang. 

'These departments are some of the most powerful institutions in North Korean political culture as they supervise the work of government, security and military organisations. 

'The Ch'angkwangsan Compound is also close to a number of venues where the North Korean leadership holds national events, as well as Pyongyang's restaurant row.' 

'And then there are a series of guest houses which are inhabited by other family members and close aides.