By Dominic Casciani
BBC News home affairs
Named as a danger to young minds, but never banned in the UK - what is the message of Islamist organisation Hizb ut-Tahrir?
Some of the books on sale at the HT conference
This coming weekend the global "political party" which campaigns for a single Islamic state across the Muslim world says it will be holding one of its largest-ever conferences in Indonesia.
But as a warm-up, some 2,000 British Muslims arrived at London's Alexandra Palace to hear the message from the party's British wing.
Hizb ut-Tahrir (HT) has been accused of being a critical player in a so-called "conveyor belt" towards terrorism - that its ideas are part of the problem.
Critics say young men, particularly students, are radicalised in private study circles to believe that being Muslim and British are incompatible because the party says Western democracy goes against a God-given set of rules.
It's this idea that critics say provides the intellectual foundations upon which violent jihadism has grown.
Hizb ut-Tahrir, which translates as Liberation Party, rejects these criticisms. The party's texts, it says, show that the proposed Islamic model of government would protect religious minorities, liberate women and enshrine justice in decision-making.
Crucially, it is a legal organisation. In the wake of the 7 July suicide bombings, former Prime Minister Tony Blair named HT as one of the organisations he would ban. The Home Office concluded after two reviews that there was insufficient evidence to ban the organisation.
Hearing the message: The platform at the HT event
Back at the conference, speakers were not however sending a polite thank you note to the Home Secretary.
Speech after speech from the platform accused Western powers of subjugating Islamic lands. In an opening address, one of the party's leading figures Taji Mustafa delivered a punchy message to the hall.
"The Muslim world wants to live by Islam, but here in the West, in London, in Washington, policy-makers, some of the journalists, are saying no the Muslim world cannot have that change. They are attacking in their speeches the call for Khilafah [single Islamic state] in the Muslim world," he said.
"We need to stand up as a vocal voice for Khilafah and expose the lies - they don't want the Khalifah to come because it will end the era of Western government interference and exploitation of the Islamic world."
Outside the conference hall, HT workers had laid out stalls of books, pamphlets and other merchandise.
Each in turn detailed the party message, often in dense prose in weighty political-science tomes. One offered a solution to Iraq; another talked about women and a Western "beauty myth"; others talked about obligations on Muslims in the West - but told them not to participate in the political system.
If the books were too much like hard work, attendees could always go for the T-shirts. "Islam the ideology alternative and solution to capitalist exploitation and hegemony," said one.
One young man from the East End of London, Asim, was wearing a t-shirt declaring he was "proud to be Muslim".
Asim said he was not a party member, but enjoyed HT talks, including small private study circles in the Ilford area. Asim also said he wanted a meeting of minds between Muslims and the rest of society. So what did he think of HT's call on Muslims not to vote?
"I think I should vote, at the end of the day it's a human right," he said. "Everyone should take part in what is going on [in society]. If you vote, you know what's going on - you take part."
At this point, two party stewards intervened. One tried to take Asim and his friends away and placed his hand over the microphone, saying that the questions were too probing and that I was using trick questions.
Another older man, who was not wearing a steward's armband, spoke to Asim and his friends and they left without completing the interview.
HT's critics say that openness is not its greatest attribute - although party spokesman Imran Waheed later apologised for the steward's intervention and said he had told staff to allow journalists to go about their business.
But on the other hand, the party won't say how many members it has - it doesn't even talk about how many study circles it runs. One informed estimate shown to the BBC puts the figures at 250 core members and 5,000 active sympathisers.
Stalls: Selling political books
Imran Waheed said membership figures were irrelevant.
"We have the support of tens of thousands of Muslims across the country," he said. "Membership in itself is not the issue - the issue is: how strong is the message."
Doesn't this leave a whiff of something to hide?
"HT is an open political party, it works openly, it's hardly clandestine," he replied.
HT has been pouring resources into developing its women's wing - and in one speech Dr Nazreen Nawaz told women in the audience that their Muslim sisters were subjugated, downtrodden and abused.
"Those women stripped of their honour in Iraq, Afghanistan, Kashmir and Chechnya, you are their voices," she told the audience. "For those women who cradle the lifeless bodies of their newborn babies in their arms at Israeli checkpoints, you are their voices."
Hizb ut-Tahrir does not seek votes - but it seeks hearts and minds for this global Islamic brotherhood, or Ummah. And Dr Nawaz's speech was one of many seeking to make the Ummah as an important, in political terms, as bread-and-butter issues such as health and education.
Neela, a London-born woman now living in Rochdale, was one of those who sympathised.
"What you will find with Muslims is that we have a global identity, we share the same relief. It's not about me being a Muslim in Britain and she's a Muslim in Palestine, she is still my sister. When I see Iraq happening, I feel sad."
"There is no one taking account of British and American foreign policy for what it is actually doing to Muslim lands.
"When we look at the solution of the caliphate, we're saying enough is enough, Muslims in the Muslim world should be allowed to choose their own political destiny. If it's Sharia law, that's their right."