In Maryhill, using the gravel-edged tone of a shipyard shop steward or a Red Clydeside radical, he shouted: "This is everyone's flag, everyone's country."
Brown's language, when needed, is more Church of Scotland minister than Cabinet minister. And no longer bogged down with baggage of party politics, back-bench squabbles or focus groups, his rhetoric flows like a brimstone-laden psalm. The right to work, the NHS, the welfare state, the commitment to international aid - Brown mentioned them and added: "These were not forged outside the Union but inside the Union, and none of us are any less Scots as a result."
Brown, now 63, doesn't think the country of his birth wants to go. "This vote isn't about a Scottish parliament, we have that. It isn't about a shared currency, we have that already. The nationalists' aim is to break every constitutional link with the UK and we will not have that. We are a nation, yesterday, today and tomorrow."
Brown had marched into the hall to thunderous applause and announced: "We are now hearing the voices of the real people of Scotland."
If he had announced he would be standing for the Scottish parliament and wanted to be next First Minister, no one would have been surprised.
If Scotland stays in the Union, if the tight polls swing in No's favour, there is an argument that points to Brown as the unexpected late-arriving saviour of a still-United Kingdom. Independent