"We are asking all of those who support Irish unity and the right of the Irish people to determine our own future, to join with us in this extraordinary endeavour, and to make it a genuine movement for change over the next number of years," Adams told the meeting.

"We have to develop a viable strategy, and positive arguments around that strategy, that can win the assent of unionists, or a significant section of unionists to a United Ireland. "

"It is clear that some unionist leaders are fearful that a substantial section of the unionist electorate is increasingly becoming indifferent to politics. "

"They are afraid that that may evolve into an indifference to the union, and they know that the potential exists to persuade a section of the unionist electorate that partition does not serve their best interests and that a united Ireland does."

"And to achieve our goals we need to mobilise opinion here in Britain, not just among the Irish in Britain but also among progressive organisations and individuals."

"We need to get people here to become persuaders for Irish unity," he added. "We need to figure out campaigns, consciousness-raising, find whatever means to get this into the mainstream of the opinion-making and decision-making processes on this island."

"The upcoming Olympics are a big opportunity. Look what the people in Tibet were able to do in publicising their cause around that, so there's a big opportunity here to start thinking around these big events."

"We need to develop a very concentrated programmatic and sustained lobby of all the political parties. I'm not just restricting that to Westminster. There are potential friends and allies in the Parliament up in Scotland, in Wales, and if they ever put together some devolved administration, here in England."

Adams gave further details of his thinking in a lively question and answer session following his speech.

Among those in the audience was Martin Collins, the director of the Agreed Ireland Forum and a long-time ally of Labour' former Northern Ireland spokesman Kevin McNamara.

"Is it possible to have a united Ireland without the break-up of the United Kingdom," Collins asked, "and if the break-up of the United Kingdom is going to be on the agenda, then how does the alliance work out with Scottish people who want independence?"

"We want to engage with people in Scotland and Wales," Adams responded. "These are live issues certainly in Scotland at this time.

The Sinn Féin President left open the question of how the party's engagement in Britain would proceed. "I've always said when I come here that I don't know how to do that here. I know how to do it at home. I could come and say the totally wrong thing on the television and annoy everybody."

"People here know how to do that. People here know how to engage. There are brilliant examples of work done in very hard times by people like Martin and others. So if you like I throw that question back to you."

Adams scotched talk of setting up a new organisation in Britain, a possibility that had caused concern among some members of Sinn Féin's existing British support group, the Wolfe Tone Society.