First Light Fusion

An Oxfordshire fusion company that uses its own amplifier technology for fusion energy and for defence and space testing.

About First Light Fusion

First Light Fusion is a UK inertial fusion energy company. Inertial fusion squeezes fuel very hard and fast to make fusion happen. In March 2025 it changed direction: it dropped plans to build its own power plant and now develops technology, including a two-stage fusion fuel system it calls FLARE, plus work for space and defence customers.

The company describes its aim as making commercial fusion possible with FLARE. Chief executive Mark Thomas said in March 2025 that the focus is accelerating the path to commercial fusion. A 2023 article quoted co-founder Nick Hawker on solving fusion with the simplest machine possible.

It was founded in 2011 as a spin-out from the University of Oxford and the team works from Oxford Pioneer Park in Yarnton, Oxfordshire. A University of Cambridge event page for January 2026 describes it as having about 80 employees in Oxford, so it was still trading in 2026.

In a February 2025 profile the chief executive described a can-do spirit and a team from varied backgrounds sharing curiosity and a wish to make a positive difference (company claims). Mark Thomas joined in 2025 after Reaction Engines and 22 years at Rolls-Royce.

We did not find a graduate scheme, apprenticeship or current vacancy list. A search result showed the company has visited Oxfordshire schools to meet future scientists and engineers, but we did not read the details. Check the First Light careers page.

What they do

• {'desc': 'A two-stage system aimed at commercial fusion.', 'title': 'FLARE fusion fuel system'}
• {'desc': 'Targets that could be supplied to other inertial fusion projects.', 'title': 'Amplifier targets'}
• {'desc': 'Gas guns and pulsed power that test materials under extreme pressure.', 'title': 'Space and defence testing'}

Key facts

• Founded 2011 as a University of Oxford spin-out
• Based at Yarnton, Oxfordshire
• About 80 employees (Cambridge event page, January 2026)
• CEO Mark Thomas since 2025

Website: firstlightfusion.com