Three British Muslims, including a former London police support officer, have been charged with travelling to Pakistan for terror training.
Scotland Yard said in a statement on Thursday that Richard Dart, 29, Imran Mahmood, 21, and Jahangir Alom, 26, had travelled to Pakistan between 2010 and 2012 "with the intention of committing acts of terrorism or assisting another to commit such acts".
The statement also alleges that the three provided others with advice and counselling about how to travel to Pakistan, find training, and how to stay safe while there.
Two others, 22-year-old Ruksana Begum and 47-year-old Khalid Javed Baqa, were charged with having material likely to be useful for terrorism.
All five had been arrested earlier this month, and at least two of the accused had previously come to public attention.
Dart was featured in a recent BBC documentary, “My Brother the Islamist”, which chronicled the efforts of his filmmaker stepbrother Robb Leech to understand why the former had rejected his family and embraced an uncompromising form of Islam.
He was also featured in a YouTube video in which he criticised the British royal family, the marriage of Prince William to the then-Kate Middleton, and UK foreign policy.
Alom - a former police support officer who was arrested in an armed raid at his home - also made a YouTube appearance in which he described his time as an officer and expounded on his hardline beliefs.
The force said Begum was caught with a memory chip carrying issues of a publication it identified as "Inspire", the name given to al-Qaeda's English-language magazine. Police said she had the documents "without reasonable excuse".
Police said Baqa was also caught with issues of Inspire, along with a CD containing the work "39 Ways to Support and Participate in Jihad".
Scotland Yard did not immediately release much information on Mahmood, but both he and Alom live near Olympic sites.
Alom's home is only 1.6km from London's Olympic Stadium, while Mahmood lives just down the street from the site of a Royal Air Force at Northolt in northwest London, from where Typhoon jets and other military elements are due to provide security for the 2012 Games.
Nevertheless police insisted the case has nothing to do with the games, which begin July 27.
Intelligence officials say there has been an expected increase in chatter among extremist groups ahead of the games, but there are still no specific or credible threats targeting the Olympics.
In late June, two Muslim men were arrested - and later released without charge - after they were spotted canoeing on the River Lee, a branch of which runs through the Olympic site.
Britain's terror level is labelled substantial, a notch below severe. A substantial threat level indicates that an attack is a strong possibility.