BBC News with Marion Marshall

Physicists working at the Cern laboratory in Geneva say they've found signs of the

hypothetical

subatomic particle known as the Higgs boson. Proof of its existence is considered crucial to supporting the standard model of physics, which explains how particles interact with each other to produce the universe as we currently understand it. However, the scientists say they'll have to carry out more work over the next few months in the hope of obtaining conclusive evidence. Cern's director general Rolf-Dieter Heuer said the findings were good news for science.

"My feeling about the achievement is excellent because I think we have achieved much more than we would have expected at the beginning of this year, and therefore, I think this was a fantastic scientific year for basic science."

The experiments were performed using the Large Hadron Collider, which

smashes

particles together at speeds approaching that of light.

A man has opened fire and thrown

grenades

from a rooftop in the Belgian city of Liege, killing three people in a busy Christmas market before killing himself. More than 120 people were injured. Matt Cole reports.

The central square in front of the Palais de Justice remains

cordoned off

this evening. The Christmas market is dark and empty, but it was very different this lunchtime. Scores were enjoying a festive shopping experience when the man now named as Nordine Amrani began shooting and throwing explosives. People began running, screaming, children amongst them. Whilst the 33-year-old attacker was known to the police, having previously faced drug and weapons charges, officers say they currently don't know why he carried out this terrible act.