Read this Telegraph article in order to understand the mindset that allowed this guy to walk around free in the first place.
It wasn't like the terrorist is a total stranger. He was on a list of suspects who were subject to "special rules" but otherwise allowed to do just about anything they wished:
The 24 year-old has previously tried to get to Afghanistan, allegedly for terrorist training, and is suspected of fighting for the Somali Islamist group al Shabaab, which has been responsible for thousands of deaths, including those of Western aid workers. He is accused of trying to recruit other Britons to its cause.
A Home Office lawyer warned after his discovery in the Olympic area that the man - known as CF - wanted to "re-engage in terrorism-related activities, either in the UK or Somalia" and is "determined to continue to adhere to his Islamist extremist agenda".
His detention is the most serious security alert yet to hit the Olympic Park.
It is disclosed today after a week which saw 14 terror-related arrests across Britain, including a white Muslim convert detained over an alleged plan to carry out a major terrorist attack.
The Olympic Park in Stratford, east London, will be protected by the largest peacetime security operation ever seen in Britain when the event begins on July 27.
CF is one of nine suspected risks to national security who are subject to Terrorism Prevention and Investigation Measures (Tpim) - legal orders which restrict their movements and computer use and who they can meet.
They were introduced to replace control orders, which were abolished by the Coalition after long-running controversy over whether they breached human rights and threatened civil liberties.
CF is being prosecuted for breaking the conditions of his order after he was arrested last month and held in police custody. He challenges the banning order at the High Court on Monday.
There are 8 other terrorists out there that authorities are presumably trailing and keeping track of. But suppose they lose one of these thugs? True, they wear a GPS tracking device, but that appears to be voluntary. Besides, such a tracking device can easily be removed if one wants to avoid the authorities.
CF has filed suit against the government accusing them of aiding in his torture when he was off in Somalia committing terrorist acts.
He jumped bail once already back in 2009, but rather than deporting him, Great Britain has inexplicably allowed him to stay in the country. It makes one wonder about security during the Olympics coming up later this month.