A former Guantanamo Bay detainee, Moazzam Begg, walked free from a British prison on Wednesday after prosecutors dropped seven terror charges relating to the conflict in Syria.
The 45-year-old, who fought in Bosnia in the 1990s and admitted training young men in Syria "to defend civilians" against President Bashar al-Assad's regime, had been in custody since March awaiting trial.
"I wanted my day in court but I was very happy," Begg told reporters outside the high-security Belmarsh prison in southeast London shortly after being released.
"I think that it's important to point out some of the government's failures in its foreign policy and its internal policy -- it's clear demonising of the Muslim community."
The Crown Prosecution Service made the dramatic announcement during a pre-trial review at the Old Bailey court in London, where Begg was appearing via videolink.
"The prosecution have recently become aware of relevant material and in light of which, after careful and anxious consideration, have reached the conclusion that there is no longer a realistic prospect of conviction in this case," prosecuting lawyer Christopher Hehir said.
Begg was arrested in February at his home, accused of providing terrorist training between October 2012 and April 2013, and funding terrorism between July and August 2013.
His arrest caused headlines because of his high profile, and police conceded that questions were now going to be asked about why he was charged in the first place.
Born in Britain, Begg fought in Bosnia in the 1990s and moved with his family to Afghanistan in 2001.
He was detained in Pakistan in January 2002 and spent nearly a year in prison at Bagram, the main US airbase in Afghanistan, before being sent to the notorious US detention camp at Guantanamo Bay in Cuba until his release without charge in January 2005.
Returning to Britain, he became director of a human rights organisation, CAGE, and a vocal critic of the rights of those detained under the so-called "War on Terror".
After the Arab Spring, he visited Syria twice, as well as Egypt, Tunisia and Libya, to conduct what he said were investigations into the British government's role in human rights violations, according to CAGE.
His lawyer Ben Emmerson said he made no secret of his visits to Syria but was not guilty of terrorism.
"Mr Begg did not train anyone for the purposes of terrorism as defined in the 2001 act," Emmerson told the court.
"Mr Begg says he was involved in training young men to defend civilians against war crimes by the Assad regime."
Some 500 British citizens are believed to be fighting for Islamic State in Iraq and Syria and Britain has stepped up checks to prevent them leaving and has arrested returnees.
In his speech to the Conservative Party conference, Prime Minister David Cameron had a message for Britons who travel to Syria and Iraq to join the Islamic State jihadist group.
"You have declared your allegiance. You are an enemy of the UK and you should expect to be treated as such," he said.