When Nicola Sturgeon strode across the gravel of Ferguson shipyard on the Clyde, one campaign ritual which has come to symbolise her popularity and dominance of Scottish politics quickly took centre stage: the selfie.

The group of bulky dockworkers wearing overalls stained by paint and oil, blue hardhats, tinted safety glasses and sheepish grins, clustered around the first minister, and several thrust mobile phones into her hands.

It was a natural Nicola moment. She flipped the phones over, and the dockers leaned in for the snap. As the platoon of press photographers massed up in front of them, one bearded docker quipped: “You want taps aff? [tops off] A bit of chest?”

This was a richly symbolic place for the first minister to stage yet another Holyrood campaign event before shein central Edinburgh on Wednesday in front of an invited audience of 1,400 activists and guests – the size of the event underlining that dominance.

Ruth Davidson of the Scottish Conservatives, Scottish Labour’s Kezia Dugdale and Sturgeon at the BBC Scotland Holyrood election debate last month. Photograph: Jeff J Mitchell/Getty Images

Yet with the SNP at its strongest, with 54 of Scotland’s 59 Westminster MPs (two of its original 56 now sit as independents, facing police investigations into alleged financial misconduct), 115,000 members and on the cusp of a second successive overall majority at Holyrood, that manifesto will downplay the one topic which defines this nationalist party most: the quest for independence.

Mindful of the black hole in Scotland’s finances following the collapse in oil prices and the SNP weakness in