A British startup developing a pioneering approach to fusion energy has successfully combined atomic nuclei – the first time fusion has been achieved using the company’s new technology.

The UK regulator described the landmark as an important step in the decades-long effort to generate electricity from the reaction that powers the sun.

Oxford-based First Light Fusion, which has been developing an approach called projectile fusion since 2011, said it had produced energy in the form of neutrons by forcing deuterium isotopes to fuse, validating years of research.

The company said it had achieved the reaction using its unique projectile method for the first time. It said the method is simpler and more energy efficient than rival approaches, and it has reached this point at record rates of progress.