Stand-up comedian Grainne Maguire has been a long-time supporter of the Labour party and regularly performs at their events and rallies. When Jeremy Corbyn was elected leader, she was happy to see the party take a decisive turn to the left. "We have a radically right-wing Conservative government at the moment. We need a clear left-wing alternative. Of all the candidates, Corbyn was the only one offering that,” she explains.

“It's not a bad thing that we now have a leader who is as left-wing as David Cameron is right-wing. Corbyn's been presented in the press as being radical, extremist – a placard-carrying lunatic – but putting his ideas down on paper, I don't think anybody would really think they're that crazy."

On the BBC’s recent Panorama tracking the rise of Corbyn, Maguire was presented as an almost obsessive supporter of the party’s "radical" repositioning – but like many young Labour members, she doesn’t class her views as extreme: "I find the 'radical' label patronising. It's a way of dismissing the genuine passions and issues facing a lot of young people today. What is radical about thinking we should have affordable housing? What is radical about saying we should support workers and make sure people are treated properly? On the issue of renationalising the railways, you couldn't have a more populist policy. There's nothing radical about these things. They’re common sense.”

Maguire doesn’t think of herself as a particularly active campaigner, but over recent months she has become more engaged with Labour’s movement, especially through social media, because of the party’s left-wing positioning and support for democratic principles.

“I like that Corbyn has a strong anti-cuts agenda and that he seems comfortable standing by the unions. We're supposed to be a party of the unions and of the people – there shouldn't be any squeamishness about it," she says. "The other candidates kind of said, 'We'll do the same things that the Conservatives are doing, but we'll feel really sad about it.' Corbyn offers an alternative; a real opposition."

Over the past week, I’ve spoken to dozens of Labour party members and supporters like Maguire with the aim of unearthing Corbyn’s most radical advocates. But what I found instead was a widespread movement; people drawn from a variety of backgrounds who have come together under the umbrella of Corbynism to support principles of equality, fairness and democracy.

Corbyn symbolises an issues-based politics and a cohesive vision for the country’s future that challenges the widely accepted political narratives that exist in society today. As well as engaging the young – a supposedly apathetic political demographic – Corbyn is building a widespread consensus around the issues that matter to people. In doing so, Corbyn has attracted the support of various fringe parties who are concerned with specific political and social issues.

“Corbyn’s rise as Labour leader opens up debates on the left, shows there is a mood for change and gives confidence to everyone fighting austerity and racism,” says Charlie Kimber, national secretary of the Socialist Workers Party (SWP). His party is thought by many to be far-left, yet there is considerable crossover between Corbyn’s principles as a social democrat and the key issues that SWP members care about.

“We oppose nuclear weapons, austerity and racism, and we are against imperialist wars. We are anti-capitalist, anti-racist and we fight for positive social change and against austerity and climate change,” Kimber explains. “We want to lay the basis of a socialist society where people come before profit. We are for socialism, and so is Corbyn. We may differ about how to achieve our ends, but we share key aims.”

Clive Heemskerk, national agent for the Trade Unionist and Socialist Coalition (TUSC), agrees that the level of consensus across campaigns from unions and fringe parties shows the extent to which Corbyn has already built a new, democratic consensus around his politics. “Corbyn’s victory has the potential to completely change the terms of mainstream political debate. We fully support his anti-austerity stance, his defence of public ownership and his opposition to Trident renewal,” he says. “We are part of Corbyn’s movement. Linking together all those who oppose austerity, defend trade unionism and support socialism, regardless of whether they hold a Labour party card or not, is the model of how the Corbyn movement needs to develop in the next period.”

In its core policy statement, the TUSC indicates that it is prepared to work with any Labour candidate who shares their “socialist aspirations” and is “prepared to support measures that challenge the austerity consensus of the establishment politicians”, but Heemskerk has concerns about the undemocratic influence of the Parliamentary Labour Party (PLP). “The 95 per cent of Labour councillors who did not back Jeremy – and the party officials nationally – have already begun to restrict his stance and undermine his leadership,” he adds. “That includes a retreat from opposing the neoliberal EU and, on rail renationalisation, waiting for the franchises to expire rather than immediately taking all the rail companies back into public ownership.”

These are examples of areas on which the fringe parties are prepared to scrutinise and even oppose Corbyn and the Labour party – surely a symptom of a healthy democratic movement, not widespread socialist "radicalisation".

“Where Labour councillors or candidates are not prepared to follow Jeremy’s stance in opposing George Osborne’s austerity agenda, the TUSC will be prepared to stand against them in local elections,” Heemskerk asserts. The SWP holds the same concerns about the PLP, and sees scrutiny and accountability as key in taking Corbyn's movement forward. “We think that these changes won’t come through parliament. We need a mass movement outside parliament and independent of Labour. The experience of Syriza and Hollande shows the problems of just winning a parliamentary majority,” Kimber adds.

Cat Conway, a PhD student in poetry, is a founding member of the Women’s Equality Party and a supporter of both Corbyn and Labour. “I am most supportive of Corbyn's policies on social issues, particularly housing, the NHS, and welfare, as well as his attitude to the economy,” she says. “I also support his re-nationalisation of public utilities and railways. Not everything has to be a for-profit enterprise: education, healthcare, utilities and public transport should earn enough to pay their staff a fair wage and maintain their services to a high standard at the lowest cost possible for the consumer.”

Like Maguire, she feels that the "radical" label is a reductive and inaccurate portrayal of the burgeoning grassroots politics that has emerged over the past few months. “I do not consider an anti-‘f**k the poor’ platform to be in the least bit radical. Radical, to me, has always been synonymous with 'irrational' and 'inflexible'. I believe in compromise. I don't believe you have to be 'centrist' to compromise,” she asserts. “The constant use of the term 'radical' is meant to frighten people, to make them feel insecure. ‘Corbyn is radical’ translates to ‘this man is out of control, hysterical, angry, and a danger to us all’, as though he's some kind of madman anarchist and not a 66-year-old man who cycles everywhere.”

Opposition to privatisation is a key part of Corbyn’s movement, and something that Jen Hamilton-Emery, director of a small literary publishing house in North Norfolk and Corbyn backer, fully supports. “I believe that this is the time that people across the party, at grassroots level, will be properly listened to. It’s a great opportunity to engage with as many people as possible, both inside and outside the party,” she tells me.

Though Hamilton-Emery has always voted Labour, she only joined the party after Tony Blair stepped down. She worked in the NHS during the New Labour years and was appalled by moves to accelerate the privatisation of healthcare by a party she felt should be opposing it in principle. With changes in the Labour party’s positioning, she now intends to get more involved with issues-based campaigning: “With Corbyn encouraging local constituency parties to discuss policies and inform debate, I intend to mobilise members and get everyone more involved. It is people on the ground that we need to engage with, inform and bring on board.”

It seems to me that those supporting Corbyn are not simply naive idealists, but rather, politically-engaged citizens concerned for those who are currently losing out in British society. “I don't consider myself radical. I see myself as standing up for and supporting the most disadvantaged and vulnerable. I don't think that Corbyn is a radical either. He's a man of strong and unshakeable principles,” Hamilton-Emery says. “But I do think that labels matter – he, and his supporters, will no doubt be called 'radical' by the press and, by extension, the public. It's reductive and potentially damaging, with no room for unpacking his message. As the Tories implement their cuts to public services, Corbyn will look increasingly radical by comparison.”

The Tories can label Corbyn and his supporters radical as much as they want, but the grassroots politics of the day seems much more likely to highlight the injustice and radicalism of Cameron and Osborne’s right-wing agenda: of tax breaks to corporations and the super-rich, of attacks on civil liberties and labour rights, of broad privatisation and of soulless ideological austerity.

What "grassroots" means under Corbyn is an issues-based and highly relevant politics. And the democratic strength of his position is self-perpetuating; the more he engages with individuals, organisations and communities about their social and political desires, the more likely he is to develop solutions in terms of policy and strategy that bring about the changes people want.

Welcome to the new British politics.