It was an unusual scenario. As the Make Poverty History demonstrators converged on the G8 summit in Edinburgh in July to press their demands, they found themselves addressed by the chancellor of the exchequer, Gordon Brown.

On occasions such as this, Brown – one of the key architects of the international debt relief plan under discussion in Edinburgh by the leaders of the world’s richest nations – is more usually to be found on the inside with his fellow finance ministers than on the outside with the demonstrators.

The chancellor, however, does not entirely see it this way. Indeed, he regards the Make Poverty History campaign as both the prime example of the ‘progressive consensus’ he wants to see Labour lead in its third term and as proof that there is a deep well of political concern and activism that the party needs to tap into.

‘We’ve got to learn from the fact that whether it’s Make Poverty History, the demonstrations for peace, or mothers getting involved in nurseries and playgroups although they’ve never done so before, people are interested in the way their community is organised, or the way the world is organised,’ Brown argues. ‘The fact that fewer people have been voting in elections is not necessarily a reflection of a lack of interest in what is happening in the world around you. But it is a challenge for modern political parties to engage people and to prove our relevance, and that’s what we’ve got to do for the next few years.’

Indeed, the chancellor dismisses the notion that in trying to recruit new members and rejuvenate themselves political parties are swimming against an historic tide – the increasing reluctance of people to join, and participate in, collective activity. Brown makes a contrast between ‘traditional organisations’ – from churches to political parties – that have suffered declining participation in recent years, and others that have ‘been born, are growing and making their presence felt.’ These organisations range from those whose concerns are very local – ‘mother and toddler groups, volunteers in early learning centres and projects’ – to those, like Make Poverty History, whose concerns are, quite literally, global.

Brown has been developing his notion of the progressive consensus – the development of what he terms ‘soundly based, radical and credible change that can be shared by the whole people’ – over the past year. With Make Poverty History, however, the theory has turned into dramatic reality, argues the chancellor:

‘It is a good example of how something that starts as the demand of a few people becomes a cause that is eventually embraced by millions. Slowly, starting with 100 people, then 1,000, tens of thousands of people and then millions, people came to the view that something had to be done about poverty in the poorest countries of the world. They came to a view that debt relief and aid was a way forward and then they came to the view that, eventually, even the Conservative party had to support.’

Brown rejects the notion that Make Poverty History and similar single-issue campaigns demonstrate the weakness and increasing irrelevance of traditional party politics: ‘Make Poverty History was outside the traditional political party process in the main, but the Labour party was directly involved, through our membership, in it. Ideally, it sends a message to us about how we should think about the future – that clearly you have to focus on what is just and unjust, fair and unfair, right and wrong.’

Indeed, the chancellor believes that Labour should take heart from the Make Poverty History experience: ‘I think the lessons we learn from Make Poverty History is that you can build a campaign that starts with sympathisers, and then becomes a group of supporters and then becomes a group of very committed people, and the Labour party is, in my view, in a position to reflect that great concern of people about these moral issues.’

Brown now wants to see Labour learn from this experience and set about forging a progressive consensus on other issues. He cites ‘educational opportunity, tackling child poverty and both the causes and the problems of crime’.

If Make Poverty History provides an opportunity, it also presents a challenge, however: ‘We’ve also got to recognise that membership of political parties is low, that turnout is not as high as we wanted it to be and that, historically, far fewer people as a proportion of the adult population are activists in political parties themselves than perhaps has been the case for the last 50 years. Now that is the challenge.’

To face this challenge, the chancellor is keen that Labour thinks radically about how it recruits new members, as well as how it retains and engages with its existing ones. The question, he believes, is not whether people feel strongly enough about these issues to take action, but whether political parties can renew themselves so they can ‘become a better vehicle for change’. It is vital, therefore, that Labour ‘reaches out beyond our traditional activist’. To do so, though, the party must ensure that it is ‘all the time talking in a language that the public will fully understand’. Labour must also, he argues, be ‘inclusive all the time, trying to broaden our constituency at every point’ and not ‘resting on our laurels with our existing membership’.

Brown sees this renewal occurring on both an intellectual and an organisational level. He is impressed by the manner in which the Swedish Social Democrats – whose summer conference the chancellor recently addressed – have managed to show that parties can ‘rejuvenate themselves in government’. He puts this down to the Swedes’ willingness to have ‘a dialogue about ideas’. At the summer conference, Brown notes, ‘they had been having a debate on all the major issues and it was a forum for an exchange of ideas.’ He continues: ‘It is very important that political parties can encourage a dialogue about what the coming ideas for the future are, and I think that is an important part of a party’s success.’

The chancellor also believes that Labour needs to reach out to the wider progressive community, attempting to engage it more directly in the party’s affairs. ‘I have always thought,’ he says, ‘that the trade unionist levy that is paid to the Labour party by individual trade unionists should be reflected in some more direct involvement by that trade unionist themself in the affairs of the Labour party.’ Brown also ponders whether there might be some mechanism by which other organisations that are ‘very strongly involved in local communities’ might be able to develop some form of ‘affiliation to local Labour parties’.

In meeting the challenge that it faces, Brown believes, Labour should also think about how it communicates with potential supporters and activists. ‘You’ve got to find new ways of communicating with people in an age where texting is as common as meeting – sometimes actually more common – and you’ve got to find a way of meeting the personal needs and interests of individual people, whether it be pensions or child benefit, and showing people that we can respond to them.’

It is clear, however, that Brown believes effecting change is the central route to re-engaging people with party politics. He recalls his speech to the Make Poverty History rally. ‘What I said to them was: don’t let anybody tell you that there are no great causes left, don’t let anybody tell you that politics doesn’t make a difference, and don’t let anybody tell you that all political parties are the same.’