"There's not a shortage of policy ideas, there's a shortage of political will," according to Hetah Shah, at the Fighting Poverty event.
During an economic crisis there was an opportuntity to refocus on environmental sustainability and well being, he said.
Shah, chief executive of educational charity DEA, said there was a lot of misunderstanding around poverty and inequality and a major education campaign was needed to address that.
He was concerned that the narratives that were emerging were divisive, not universalist.
If you were looking for an activism model then progressives should look towards the green campaigners. Those on the progressive left had to reach out to those campaigning on green agendas and convince them that campaigns about sustainability and poverty went hand in hand, he said.
The Green Party's Sian Berry said the ideas of a green new deal were now gaining more political hold, as investing in green industries and sustainability were now being discussed in the mainstream as a way of creating more jobs.
"It's great to hear this sort of thing being discussed in America. it's great to hear Gordon Brown talking about it."