London Maori group Ngati Ranana performed a welcome ceremony in The Scoop next to City Hall on Monday to launch a two-week festival of arts from the indigenous cultures of Australia, Canada, New Zealand and the USA.
"I'm here in my capacity as an English actor, working for the last 35 years in theatre, film and television in England," said guest of honour Pete Postlethwaite who has most recently been seen in King Lear at the Young Vic.
"It is with awe, wonder and anticipation that I welcome all the first nations to London to this Origins Festival.
"In a world of economic meltdown and global warming – twin catastrophes of corporate greed and pure blindness – I tend to agree with Evo Morales, the first indigenous president of Bolivia, who said 'I'm convinced that the indigenous people are the moral reserve of humanity'.
"You all – as artists – represent that moral minority. And as an English artist who is just learning a little about what you already know I wholeheartedly welcome you to London, England and this prestigious Origins Festival.
"May the spirit guide us all and let the good times roll."
Festival director Michael Walling made an impassioned address highlighting the political, economic and environmental "violation of moral law" by western countries in the past few centuries.
"It's at times like this that we need guests like these," he said.
"Because our way of life is really proving itself not to be sustainable. More than that: it's proving to be disastrous for the future of the planet.
"And so we need to show at last a little bit of humility and recognise that there are other people in the world who we have dominated and marginalised for too long who have ways of living that are sustainable and who perhaps can teach us a thing or two."
Although all the main events of the Origins Festival are north of the river, the closing ceremony will be held in The Scoop on Sunday 17 May.
• Full programme at www.originsfestival.bordercrossings.org.uk