The search for cheap and abundant sources of power is as old as perpetual motion machines. The promise of a limitless and clean energy source, ending our dependence on the Middle East and curbing the greenhouse gases causing climate change, has kept thousands of Oxfordshire scientists busy since the 1960s.

The researchers at Culham are engaged in the battle to produce energy from nuclear fusion — the reaction that powers the sun. Fusion is markedly different from current nuclear power, which operates through splitting atoms — fission — rather than squashing them together in fusion.

Since the H-bomb was invented, fusion has been the holy grail of power seekers, but it has proved difficult to put into practice. Nevertheless, the potential rewards are so high that governments worldwide are pouring money into it. For fusion to happen, the atoms must be kept extremely hot and under such high pressure that they form 'plasma', a soup of charged particles.

While nuclear fission power stations are keeping the lights on all over the world, nuclear fusion experiments have yet to produce enough net energy to boil a kettle.

The earliest estimates of when a fusion power station could be built are decades in the future. At the moment, Oxfordshire is leading the field, with the Jet project at Culham being Europe's biggest fusion device, and arguably the most advanced in the world.

The Jet machine, with its doughnut-shape ring of plasma, is known as a 'tokamak', named by the Russian scientists who first developed the concept.

Jet employs 1,100 people and receives £63m a year in European funds.

Steve Cowley, chief executive of the UK Atomic Energy Authority, believes that one day it will be a commercial enterprise.

In the meantime, dozens of private companies are already cashing in on Culham's unique expertise. The latest entrant is Tokamak Solutions, which has raised £170,000 from investors for a project almost as ambitious as the aim of a fusion power station.

Instead of producing energy from fusion, they are aiming to produce atomic particles known as neutrons.

Chief executive David Kingham said: “It's a huge challenge, but we have worked out that the tokamak technology could be useful more rapidly if you consider it as a neutron producer, rather than an energy generator.

“It doesn't matter if you are putting more energy in than you get out, if the neutrons are valuable enough.”

And they are valuable — in high demand from researchers wanting to produce new isotypes for cancer studies, as well as those trying to 'transmutate' nuclear waste to make it safe.

Instead of copying the massively expensive Jet machine, Tokamak Solutions will use the methods of a rather cheaper, smaller machine called Start, which was built at Culham in the 1990s in a matter of months, for a fraction of the cost of Jet. Start had a compact, more spherical shape than Jet — a cored apple rather than a doughnut.

Mr Kingham said: “The Start spherical tokamak was a story of British ingenuity — working on a shoestring, using equipment that happened to be lying around — rather than big science. It was ground-breaking at the time, and the quality of the plasma was astoundingly good.”

By coincidence, one of Tokamak Solution's founding scientists, Mikhail Gryaznevich, is Russian, having been poached in the 1980s to create Start at Culham with colleague Alan Sykes.

Tokamak Solutions’ mini apple-shaped machines, while cheaper than Jet, will still cost a million dollars each and take more than a year to build. Mr Kingham admits it would be rash to spend money building a machine before they have found a customer, but is optimistic.

He said: “All those involved are aware that it is high risk, but the possible applications are exciting.”

n Contact: Tokamak Solutions. 01865 408303. www.tokamaksolutions.co.uk