Gordon Brown was hemmed in between the soft fruit and the yoghurt at a supermarket in Livingston. The former prime minister crouched down between two small children while their mother lined them all up in front of her camera phone.
"C'mon Gordon," she shouted at him, "You are supposed to smile you know."
Mr Brown put on a forced grin but it was clear he was finding it hard to look chirpy. He was not alone. Such has been the atmosphere of desperation and near panic in Labour ranks in Scotland that the blaming and backbiting over this election campaign has already started – and polling day is still 24 hours away.
The reason is simple. Labour in Scotland had a solid 10-point lead over the SNP just six months ago. Although its lead had dropped to single figures by the start of the campaign in March, the Labour leaders were still confident of winning.
But over the course of the campaign that advantage has not just vanished, it has been turned into such a thumping SNP lead that the latest poll published last night by TNS-BMRB for Scottish Television forecast abject humiliation for Labour tomorrow.
That poll gave the SNP a whopping 18-point lead on the constituency vote and a 13-point lead on the list vote. This was not a one-off, though. It was merely the latest in a series of polls creating "clear tartan water" between the Nationalists and their rivals – according to Alex Salmond.
The SNP's 2007 Scottish Parliament victory (by a single seat) was seen by many observers as a blip, an aberration, something which would be righted this year. But if Labour loses again tomorrow and, more importantly, if Labour loses by a substantial margin, then it will be clear that the ground has shifted in Scottish politics, perhaps forever.
Labour strategists acknowledge privately that chief among their problems has been the campaign message. Labour went into the election with a defiant anti-Tory theme: the Conservatives are back in charge at Westminster, so vote Labour to stand up for Scotland against Tory cuts.
It was designed to press all those old Scottish working-class buttons about the Tories and invoke bitter memories of Thatcherism. But Labour's message was so ineffectual that the party had to switch tack with just two weeks to go. In a hasty relaunch – devised in frantic calls to concerned party bosses in London – Labour stopped attacking the Tories and turned instead on the SNP. The message became a straightforward if negative warning about the dangers of Scottish independence.
Labour's biggest challenge has been countering the Alex Salmond effect. The SNP leader is the biggest beast in the Scottish political jungle, with an extraordinarily high recognition factor among the electorate.
Labour's alternative, Iain Gray, is – unfortunately – just that. A decent and passionate politician, he has found it almost impossible to rise above a reputation for mediocrity and appear as Mr Salmond's equal, let alone emerge as a better choice for the First Minister's job.
Mr Gray performed nervously in the first television debate and then had to endure a gap of nearly four weeks to the next one, during which time Mr Salmond and the SNP built an apparently unassailable lead.
Labour has suffered from some self-inflicted wounds. The party's manifesto launch was halted first by a fire alarm, which left the media standing in the rain and then by a proof-reading error which committed Labour to abolish "failed Scottish Labour" instead of the "failed Scottish Futures Trust".
Unfortunately for Mr Gray, the abiding image of the campaign was of him cowering in a sandwich shop in Glasgow Central Station surrounded by anxious, over-protective spin doctors while anti-cuts campaigners demanded to speak to him outside.
Labour needed everything to go in its favour and for the SNP to stumble for it to head into tomorrow's election with a good chance of winning, but the reverse happened.
The Labour campaign has been plagued with gaffes and errors, there have been poor performances from key players and, most important, the main message was hopelessly misjudged.
At the same time, the SNP has run a smooth, gaffe-free and unexciting campaign but it is one which looks like it may well propel Mr Salmond back to power tomorrow. If that happens, then not even the most persuasive mother in a supermarket is going to get a smile out of Mr Brown – not for some considerable time to come.