In the crucible of the 2017 general election, a small group of progressive activists set about trying to change British political life for the better. Armed with the conviction that the old politics was irretrievably broken, the progressive alliance set itself the task of breaching the walls of Britain's tribal political culture.

Over the seven weeks of the campaign, even as the struggle between Theresa May and Jeremy Corbyn built up to a stunning and utterly unexpected climax, the progressive alliance fought its own battle. Its aim was to bridge divides, start conversations and forge alliances on the ground between progressives – socialists, social democrats, liberals, Greens, Welsh and Scottish nationalists – working together against their common foe instead of competing self-destructively against one another.

Based on first-hand testimony, All Together Now tells the dramatic story of how the progressive alliance helped shape the story of the 2017 election – and why its aims, its methods and above all its values will shape the future of 21st century politics.