By Dan Rivers and Jonathan Wald reporting from London
News that European intelligence agencies are searching for a so-called "clean-skin" al Qaeda operative with a European passport should not be surprising.
It has long been the ultimate terrorist weapon: a convert with no previous convictions, who is not "on the radar" of intelligence agencies. Yemen is currently a go-to destination for young Jihadis and al Qaeda in the Arab Peninsula seeks to host clean-skins as it continues to attempt to attack the West. But there is no suggestion that this alleged plot is connected to the Olympics and the perpetrators may already have put their plans on hold, worried they are about to be discovered amid widespread news coverage.
The only tangential connection to Olympics is simply it may have happened in the same year as the games. But with Britain currently experiencing a credible terrorist plot about once a year, according to a recent speech by Jonathan Evans, the director general of Britain's domestic security service MI5, it's likely the authorities will uncover a plot involving Britain at some point in 2012, according to some experts.
In fact, it's understood MI5 is prepared for a doubling of leads in the run-up to the games. Why? Because analysts will be less inclined to dismiss minor threats, because of the magnitude of the event and are being even more cautious than normal, no matter how remote the possibility of a credible threat.
This heightened vigilance creates more leads, which are passed up the chain of command. In addition, security experts say more members of the public may talk about carrying out an attack during the Olympics, while having no intention of doing so. As a result, this "idle chatter" gets picked by up by Britain's surveillance centre GCHQ in Cheltenham, creating even more paperwork.
It's understood MI5 is already completely focused on the Olympic games, shutting down non-essential training to ensure it has as many personnel as possible watching for threats. There are a number of areas from which that threat could emerge. Al Qaeda is the most obvious, but there are others. The Irish Republican threat, from splinter groups like the Real IRA, remains in the UK, although an Irish Republican attack on the Olympic games is considered unlikely, because of the bad PR it would create. The devastating bomb in Omagh in 1998 is often cited as an example of a republican terrorist atrocity that was so horrific it alienated some who may have been otherwise sympathetic to their cause. More likely is a hoax bomb threat from the Real IRA, which would cause disruption without fatalities.
There is also the risk of other foreign terrorist groups bringing their domestic disputes to the UK, like the Palestinian Black September Group did at the 1972 Munich Olympics, when they kidnapped Israeli athletes.
But the world's intelligence services will be descending on London to try and prevent any terrorists from carrying out an attack. The Olympic Intelligence Centre will provide analysis of threats to visiting security officials from countries competing at the games - it's fair to say there will be more people watching for threats this summer than at any other time in recent British history and therefore if you're a terrorist, you've got more chance of being caught. That doesn't mean an attack is impossible, but the British authorities are confident they are doing everything they can to make an attack much more difficult to carry out.
As MI5 Director General Jonathan Evans points out, "You could say that we are near to reaching a form of stalemate - they haven't stopped trying but we have got better at stopping them. That is normally as much as security on its own can achieve."