The scientists who announced they had recorded subatomic particles called neutrinos breaking the speed of light last year have found a small problem.
The results could have been skewed by a dodgy cable, according to the physicists at Cern, home of the Large Hadron Collider particle accelerator.
Their experiment sent the science world into uproar as they appeared to have blown open Einstein's 1905 theory of relativity - a cornerstone of physics.
It states that no particle can travel as fast as light in a vacuum because light has no mass.
In September they beamed neutrinos over 450 miles from their base in Geneva to a laboratory in Gran Sasso in the Italian Alps.
The neutrinos beat light by 60 nanoseconds - or billionths of a second - raising science-fiction-style scenarios blurring the lines between past and present. When they repeated the experiment, known as Opera, two months later just to make sure, they got the same result.
But yesterday they announced they had found a couple of snags.
One was a problem with an oscillator on the global positioning system used to track the neutrinos' progress. This may have overestimated their flight time.
The second was with the optical-fibre connector that joins the GPS signals to the master clock at Cern that recorded the result.
Unfortunately, they said, 'this may not have been functioning correctly when the measurements were taken'. They added: 'If this is the case, it could have led to an underestimate of the time of flight of the neutrinos.'
They will have to study these two effects and calculate new measurements that are expected to be released in May.
University of Surrey physicist Professor Jim Al-Khalili, who promised to eat his boxer shorts on live TV if neutrinos were shown to travel faster than light, said: 'I suspect, now more than ever, that both Einstein's theory and my boxer shorts are safe.'
- Daily Mail