Late evening sunshine warmed the grand interior of Westminster’s Emmanuel hall on Tuesday night, where over a thousand people had gathered to discuss the need for “Post-Brexit Alliance Building”.

The building itself, inscribed with biblical quotes, could not help but set a tone of business-as-usual. But this was part of the problem the speakers wanted to address: how can the metropolitan bubble reconnect with those turned off by politics?

According to the assembled politicians – Shadow Defence Secretary Clive Lewis, Green Party MP Caroline Lucas, the SNP’s Tommy Sheppard, and the Liberal democrat’s Vince Cable - there is now an urgent need to reach out to those who feel politics has failed them. And who may have voted Leave as a result.

Green Party MP Caroline Lucas was first to take to the podium, where, like a fairy-godmother come to rescue listeners from disappointment, she laid out her battle-plan for a better Britain and a better democracy:

“The Tories are readying themselves now for another round of disaster capitalism using the post-Brexit turmoil to further shape the economy in their interests," she said. "I believe we need to prepare for that and lobby for an early general election.”

"[We need to] prevent the formulation of a Tory-Ukip government that would enact an ultra-right Brexit scenario, I think there should be a pre-election pact between Labour, the Greens, the Lib-Dems and Plaid together. And that the glue holding together such a pact would indeed be a commitment to Proportional Representation.”

Yet a more inclusive politics, she suggested, should also be built within the system as it currently stands - by harnessing grassroots energy, signing up individual candidates to a core set of progressive principles and pressing for more open primaries and non-aggression pacts. And, not least, in and seeking to pull opportunity from the jaws of defeat:

“The referendum was a wake-up call. Lets honour it by rejecting xenophobia, lets rise to it by pledging to share the economic benefits of migration with the many, lets respond to it by giving real power to the people with a voting system that genuinely allows their voices to be heard.”

Some may have been disappointed that a call to reject the referendum result was not part of her agenda. But Lucas’ message of conciliation was clear:

“In my heart of course, I believe Britain’s future should be in Europe [...] but friends, I believe that to seek to overrule the outcome of the referendum is bad politics and worse democracy. What better way to reinforce the belief that the metropolitan elite care nothing for the views of predominantly working-class people in disconnected communities, than to seek to ignore their views and overturn the result.”

Labour’s Shadow Minister for Defence, Clive Lucas, the Lib-Dem’s Vince Cable and SNP MP Tommy Sheppard all echoed Lucas on this position. Yet it was the speakers from outside the seats of government that drove home the point to greatest effect:

“Please let’s not think about the vast majority of people I've talked about who voted Leave as stupid, or deluded, or bigoted, and hateful”, pleaded Guardian journalist John Harris. “If you woke up on Friday morning thinking that the country you lived in was suddenly being controlled by a social tribe you didn't know much about and you suddenly felt terrified about the future, bear in mind that’s how millions of people in this country have felt for decades.”

Harris’s account of his experiences reporting outside of London, particularly in his native Wales, helped ground the talk of Westminster squabbles and Brexit bungle in the deeper, longer story of Britain’s industrial decline:

“About two years ago, in 2014, around the time of the Scottish referendum, John and I made a film set in Penegraig, in the Rhondda valley in South Wales. It's a place where my family is from, so I know it, and it's a place missing what I used to associate with it – coal mining. And nothing has come along to replace coal mining at all really in that place – and it feels like it has an emptiness, really, at its heart. It’s a place we still call a ‘Labour heartland’ and it still has a lots of heart – but its affinity with the Labour party (you only need to go around and talk to people to know) has waned. ”

Most popular of all however, at least with the younger audience members I spoke to, was the appeal of singing teacher and Take Back the City organiser, Amina Gichinga:

“It would be a mistake to think that we just need to get rid of the Tories. The forms of political organisation that we have at the moment are inadequate and they’re failing to engage the vast majority of people in London and the rest of the country. Obviously we would prefer a left-leaning progressive alliance to a Tory government. But this isn’t about left-leaning political parties working together - it isn’t going to be progressive if parties don’t change the way they do politics and make it more open to young people, people of colour, women, working class people, migrants, refugees - people who lack a political voice but make our city and our country what it is.”

The obstacles to such a vision are not insignificant. Clive Lewis’ speech highlighted the internal disputes occupying Labour, as well as hinting at reservations surrounding Proportional Representation.

Comments from the floor touched on a range of further considerations. “I fully support a progressive alliance but I also oppose oppositional politics,” said a representative of Makes Votes Matter. “Our campaign certainly welcomes Ukip supporters, Tory supporters, and I really believe that we have to work together to include everybody if we want to get PR”.

But, overall, the message was one of action that starts at home. “If a change to the system [of first past the post elections] means I will have to give up my seat tomorrow, I will gladly do so”, volunteered the SNP’s Tommy Sheppard.

There are also plans afoot to repeat similar gatherings around the country. Tonight’s event in Brighton will see Neal Lawson and Davy Jones discuss the Progressive Alliance. While Compass, the left-wing pressure group responsible for organising Tuesday’s event, has plans to stage at least five bigger meetings out in Brexit heartlands. These will be accompanied by an online engagement platform and a callout for self-organised meetings that can feed back in to eachother.

In the words of John Harris: “Let’s go out of this stateless country that some people are calling ‘Remain-ia’ ... Let’s go out into the country and reinvent our politics”