Given an opportunity to set out his stall inside the conference hall earlier, he declared: "The neo-liberal experiment is dead and we must now articulate to an angry country what will replace it. "That must be a country where markets serve people and not the reverse."
He told the Fabian Society event that it was 'time to let Labour be Labour'. Welsh Labour had an opportunity to "lead the charge" on combating child poverty, he said. He estimated that Labour's target of halving child poverty by 2010 would cost Wales an extra £150m.
"That's a do-able deal," he said. "That's a level of commitment that's achievable by the Welsh Assembly Government. The fear of a spending squeeze during the economic downturn must not "paralyse" Labour into believing "that really all you can do is to retreat into a bunker of political management". "We need to attack this recession not just manage it."
Another potential leadership candidate Carwyn Jones AM was emphasising a green jobs agenda.
Lewis also suggested last week that both he and Jones both believe in challenging the culture of Welsh politics, arguing that 'smeargate' could prove a wake-up call for a political culture where personal attacks too often crowd out a battle of ideas.
Finance Minister Andrew Davies (who also spoke at Saturday's Fabian fringe), Health Minister Edwina Hutt and Glamorgan AM Jane Hutt have all been mentioned as possible candidates.
Wales on Sunday has some speculation about possible runners and riders, though I am not well placed to know how accurate this is.