The culprit at the time was a poorly-soldered electrical splice, which overheated leading to a series of problems that damaged 53 of the LHC’s 1,624 magnets, among other components.

Now, after  around €40m  in repairs the LHC is ready to get back to its task of smashing together particles traveling around a ring in opposite directions to shed light on the fundamental structure of matter and the origins of the universe.

Scientists at the European Organisation for Nuclear Research (CERN) say they have established circulating particle beams in both directions. The CERN team has decided to take things slowly, starting at just 3.5 trillion electron volts per beam – half of the 7TeV that was originally intended.

But if things continue to go smoothly they say they may be able to accelerate particles at the highest energy level ever tested before Christmas, although the full 7TeV collisions wouldn’t happen until next year.

CERN scientists, also  took advantage of the extra time to increase the sensitivity of the safeguards at the LHC, so that if the collider is beset by another mishap, it would not sustain the same amount of damage as it did last year.

Now that the LHC has established circulating particle beams, next step is  low-energy collisions that are expected to begin in around a week's time. The high-energy collisions are expected to commence in January 2010.