When Alex Salmond speaks, respond as though to a very bad smell.
It doesn't matter what he might have to say. It doesn't matter that your own argument might be a little frayed around the edges. At all costs, behave as though the very existence of the First Minister is offensive to decent folk.
Lamont is good at this, mostly because she doesn't have to pretend. Like most of her colleagues, she really can't stick Salmond. Like most of them, she detests above all his alleged habit of claiming credit for every success and blaming London when things go wrong.
This week's dire unemployment figures should have qualified, then, as fish in a barrel. Wasn't it just last summer that Scotland's seeming reprieve from economic doom was supposedly the result of splendid SNP policies? Yet here he was grumbling that he had "no ability to increase demand in the Scottish economy".
Lamont's body language shouted her distaste. The nose was wrinkled, the eyes narrowed, the mouth pursed: half a novel was written on her face. With 200 Scots losing their jobs every day – she got that figure into every other sentence – how dare he?
Silly question. Silly as a multi-storey car park on a busy Saturday: on several levels. First, don't bother even to ask what Salmond would dare. Second, don't doubt what he believes. He really does think he could fix most things with those magical "economic levers".
Thirdly, don't be silly enough to think he'll let you forget your own Labour loyalties. After all, Lamont's opposite number in Wales has been agreeing with the First Minister – says the First Minister – while Ed Miliband is "in cahoots", suddenly, with the Coalition. Salmond loves that weird phrase.
"I didn't expect to get hunt-the-alibi quite so early in the process," said Lamont. She later accused the First Minister of "breathtaking" – isn't it always? – complacency. But here, in miniature, was the problem that haunted each of her predecessors.
Nothing Salmond says can be tested until he gets the thing Unionists refuse to grant, which is to say independence. But if his ambition is thwarted, he will always have that "alibi". If independence is achieved, meanwhile, it will be too late for Labour to say "told you so".
The smell Lamont detects is called "fishy".
Alison Rowat: Page 11