Ministers are ready to approve the swift development of a fleet of “mini” reactors to help guard against electricity shortages, as older nuclear power stations are decommissioned.

The new technology is expected to offer energy a third cheaper than giant conventional reactors such as the ongoing Hinkley Point in Somerset.

Industry players including Rolls-Royce, NuScale, Hitachi and Westinghouse have held meetings in past weeks with civil servants about Britain’s nuclear strategy and development of “small modular reactors” (SMRs).