An international project has announced plans for the largest radio telescope ever constructed.

The Square Kilometre Array will have a collecting area of one million square metres, making it 200 times bigger than the University of Manchester's Lovell Telescope at Jodrell Bank.

Such a telescope would be so sensitive that it could detect TV broadcasts coming from the nearest stars.

The concept was first proposed to observe the characteristic radio emissions from hydrogen gas. Measurements of the hydrogen signature will enable astronomers to locate and weigh a billion galaxies.

"Hydrogen is the most abundant element in the universe, but its signal is weak so a huge collecting area is needed to be able to study it at the vast distances that take us back in time towards the Big Bang," said Peter Wilkinson, professor of radio astronomy at the University of Manchester.

The European Commission's Framework 6 Design Studies programme is contributing about 27 per cent of the total £38m funding over the next four years. Individual countries will contribute the remainder.

The UK has already invested £5.6m and, when coupled with the its share of the EC contribution, the UK's overall contribution is about 30 per cent of the total.

"Designing and building such an enormous technologically advanced instrument is beyond the scope of individual nations," said Professor Richard Schilizzi, the telescope's international project director.

"Only by harnessing the ideas and resources of countries around the world is such a project possible."

The location of the telescope has yet to be decided but several countries in the EU have applied.