Just 24 hours after North Korea test-fired its Hwasong-15 intercontinental ballistic missile (ICBM) in November last year, Kim Jong Un promptly declared that the DPRK had successfully completed its “state nuclear force”.

Coming after 17 separate missile test events in 2017 – which featured at least five new designs – the declaration was the first clear indicator that Kim’s appetite for high-frequency missile testing was about to change.

But while the sheer range and power demonstrated by the single HS-15 test blew away some who had ridiculed the poorer performance of two Hwasong-14 ICBM tests last year, the combined