The findings appeared to upend the fundamental laws of physics.
Albert Einstein proposed 100 years ago that nothing could travel faster than the speed of light in a vacuum. It underpinned the Standard Model of physics, whuch explains the way the universe and everything in it works.
But in September 2011 workers at CERN, the world's largest physics lab, announced they had recorded subatomic particles travelling faster than the speed of light.
They recorded neutrinos travelling at 300,006 kilometres per second in a 450-mile underground tunnel between Switzerland and Italy. Light travels at 299,792 kilometres per second.
Antonio Ereditato, spokesman for the researchers, said at the time: “We have high confidence in our results. We have checked and rechecked for anything that could have distorted our measurements but we found nothing.”
Today CERN physicists have admitted a faulty connection between a GPS unit and a computer may be to blame.
Professor Brian Cox, a particle physicist at the University of Manchester and television presenter, said at the time that, if the result were proven, it would be the most profound discovery in physics for a century.
Dr Giles Barr, a physicist at Oxford University, said the results had "mind boggling" implications.
The scientists on the Oscillation Project with Emulsion Tracking Apparatus, or Opera, had conducted more than 15,000 measurements over three years before announcing the results.
In November the scientists said a new set of experiments had confirmed the result and ruled out one source of systemic error. A team of Russian, American and British scientists promised to test the findings using a laboratory running from Chicago to the Canadian border.
But many were sceptical.
A rival team at the CERN lab, working on a project dubbed ICARUS, said the particles had not lost as much energy as they would had they been travelling at superluminal speed.
Professor Stephen Hawking, of Cambridge University, said: "It is premature to comment on this. Further experiments and clarifications are needed."
Dr John Costella, an Australian physicist, said the researchers had made an "embarrassing gaffe".
"Any physicist worth even a fraction of their weight in neutrinos will be shaking their head, knowing intuitively that the OPERA result is simply wrong," he wrote in an online paper.
And Dr Jim Al-Khalili, a professor of Physics at Surrey University, said: "If the neutrinos have broken the speed of light, it would overturn a keystone theory from the last century of physics."
He added: "That’s possible, but it’s far more likely that there is an error in the data. If the CERN experiment proves to be correct and neutrinos have broken the speed of light, I will eat my boxer shorts on live TV.”