The British Council brought together 21 young activists from the countries that will be represented at the London Summit to formulate their manifesto for the world’s leaders. Assunda from South Africa presented the ideas of the Global Changemakers group to UK Foreign Secretary David Miliband, at an event shortly before the Summit in Parliament’s House of Lords. Mr Miliband said he found the dynamism and idealism of the group 'hugely impressive'. He added: 'To effect change in the modern world, you don’t just need governments, you need citizens.'

• Global Changemakers present their G20 manifesto to David Miliband

Interviews with individual Changemakers found remarkable agreement on priorities for the London Summit. Diego  from Brazil said his priorities were the social issues – the fight against poverty and for social development. 'We are putting our hopes in the London Summit,' he said. 'Everything that comes out from that meeting will affect us for the coming years.'

• Diego from Brazil

Mimi from Japan said all the Changemakers came with their own proposals, but found a community of ideas around education and development. 'Young people want to see progress: we've seen how much we could accomplish in two days … that's something we really want leaders to do.'

• Mimi from Japan

Andreas from Germany said the Global Changemakers event had been a wonderful opportunity to address world leaders about the concerns of young people. 'I feel particularly strongly about climate change: if we don't tackle it today, it will affect us all tomorrow.'

• Andreas from Germany on the G20 Summit

Assunda from South Africa said the Global Changemakers had been able to bring together people who were activists who knew the issues of concern in their own countries. 'We are young, idealistic and optimistic – but we have to be realistic. The objectives we have set out for our leaders are achievable.'

• Assunda from South Africa