What would really happen if they created a black hole?

First there would be an explosion so massive it would instantly destroy the Earth.

Then the material remaining would be sucked into an infinitesimally small space at speeds approaching the speed of light. Finally, a massive burst of energy would see X-rays spat out by the black hole.

The doomsday scenario predicted by some critics of the Hadron collider is not short on drama - but today experts said it was very short on probability.

Professor Jordan Nash, an Imperial College scientist who is also involved in the Cern project, said it was near to impossible to imagine such a possibility. The 15,000 Cern scientists are sure it will not create a black hole.

Even if it did, it would be a minuscule version of the massive cosmic phenomena which occur when giant stars collapse on themselves. Finally, if tiny black holes can be created, they would evaporate in a flash of gamma radiation, instead of sucking in mass around them.

"If we were to create a black hole at Cern, which we are certain will not happen, it would be a very tiny one, smaller than a cell in your body," he said. "I think the worst we will see today would be a power cut which meant we had to delay the experiment for a short time. Nothing could go wrong on the scale of a star collapsing, which is what some people have been talking about," he said.

"To create a giant black hole would take a star much bigger than the sun to collapse. We are not doing anything that doesn't occur in nature every day, and in our own atmosphere."