Oxfordshire scientists have reached the final milestone of the UK's biggest science project for 30 years.

The team at the Diamond Light Source, at the Harwell Campus, have succeeded in focusing the light source into an intensely powerful beam and delivering it to three experimental stations, where it can be used to study the structure of matter.

Chairman of the Diamond Users, Prof Trevor Rayment, said the £250m Diamond machine, which is the size of three football pitches, looked a bit like a doughnut or stadium.

He added: "Unlike Wembley, it was built on budget and on time - at about a third of the cost, and it's above specification. It's a lab where world-class scientists can carry out premier league science, and you can trust that we will."

Prof Rayment said the 'supermicroscope' - known as synchrotrons - would allow scientists to find new materials for environmentally friendly fuel sources, and look at the structure of everything from aeroplane turbines to new drugs to combat cancer or flu.

The first phase of the massive construction project is on schedule to finish in January 2007. Work started in 2002 and involved sinking 1,500 concrete piles 15m deep below the chalk to stabilise the huge machine.

It now employs 270 people and by the time it is working to full capacity in 2008, it will recruit another 80. Last week, the team was congratulated when Prime Minister Tony Blair paid a visit.

Many of the optical components were made by Oxford Danfysik, based in Osney Mead, which is a worldwide expert in the specialist technology of beamlines.

Formerly Oxford Accelerators, the company was bought from Oxford Instruments in January 2001 by Danish company Danfysik.

Its beamlines and components are used in synchrotrons worldwide, including the European Synchrotron Radiation Facility in Grenoble, France, where many British scientists are basing their research while they wait for the Oxfordshire machine to be completed.