Getting to grips with the global recession ahead of next week’s G20 gathering, world leaders are keen to demonstrate a united front.A pre-summit warm-up in Chile has heard clear calls from the centre-left for widespread financial reform. But, from Barack Obama’s second-in-command, there was also a warning about the risks of over-regulation. “We should not over-react,” US Vice President Joe Biden told a round-table discussion in the coastal resort of Vina del Mar. “This is not a choice of markets or governments, in my view. Markets are still…a free market still needs to be able to function.” The US President has played down evidence of a transatlantic rift over whether the G20 should emphasise spending or regulation. But analysts say Washington is pushing Europe to spend more as a way out of the crisis, while Europe wants to prioritise reform. Whatever the focus of the talks in London, tens of thousands of demonstrators are determined to make their voices heard. Yesterday’s rally in the British capital helped kick off a series of pre-summit protests urging those in power to act on poverty, jobs and climate change.