The UK’s decision to back construction of a new generation of nuclear power plants makes it an important testing ground. Investors wanting to build and operate plants will benefit from the streamlined planning process and licensing regime announced on Thursday. But key ingredients are still missing. The most vital of these, a stable price for electricity generated by nuclear energy, is far from guaranteed.

The case for nuclear is attractive. Without it, the UK stands little chance of meeting tough targets to cut emissions of carbon dioxide. Like other European countries, it also risks becoming too dependent on natural gas imports for its energy needs. Renewable sources of power such as wind, solar and wave energy emit no carbon. Unlike nuclear, they are either not sufficiently reliable or cost-effective enough to meet baseload electricity demand. Moreover, not replacing ageing nuclear plants would add to emissions.