Hitachi has suspended work on its nuclear new-build project at Wylfa, North Wales. Despite six months of negotiation and the key elements of a support offer from the government in place, Hitachi is unconvinced the £20bn project will be economically viable as a private enterprise. This is a major blow to nuclear’s role in UK power supply and government energy strategy. With the decline of its aging reactor fleet and a phase-out of coal in the mid-2020s, the UK will see renewed focus of gas-fired generation alongside renewables. With limited gas storage availability and declining indigenous supply this change raises energy security concerns. While the government may consider alternative funding models and new technologies to deliver nuclear, it would be prudent to refocus on wind, solar and decarbonised thermal sources as the mainstays of future power supply.