In his telephone call with Rupert Murdoch last Tuesday evening, Gordon Brown, while keeping the tone friendly, warned the owner of The Sun that his paper was effectively undermining Britain's mission in Afghanistan.
By attacking the Prime Minister over his misspelt handwritten letter to Jacqui Janes, the grieving mother of a dead soldier, the newspaper was questioning the Government's commitment to troops and therefore, it was suggested, destabilising the war effort.
The News Corp chairman disagreed with the charge against The Sun, which portrays itself as the forces' newspaper, saying that this was clearly not the impression anyone wanted to take from the episode. Mr Murdoch added that he had great respect for the Prime Minister.
But by the next morning, perhaps not entirely by coincidence, The Sun had softened its position. After its earlier highly personal and sustained attack on Mr Brown, it described the intention of his correspondence as "well meaning".
It marked the moment when, after what had begun as yet another difficult week for the Prime Minister, the scales tipped in his favour.
The omens did not bode well when, at the Cenotaph for Remembrance Sunday, Mr Brown failed to bow his head after laying his wreath of poppies. Downing Street insisted he was disoriented because of his eyesight.
Then, at 6pm that day, No 10 officials took a call from The Sun, which broke the news that they were splashing with the story about Mrs Janes and her son, Pte Jamie Janes.
The phone call was regarded as a little late in the day, but at least it was a more advanced warning than the Prime Minister received on the evening The Sun switched allegiance to the Conservatives during the Labour conference in September – which came barely minutes before the newspaper's first edition was published.
On Sunday evening, Mr Brown decided to telephone Mrs Janes – another attempt to engage with her directly and personally. But this move backfired when, while taping the conversation, Mrs Janes rounded on him about lack of equipment for British troops.
The call provided fresh material for The Sun on Tuesday. But the tone of its coverage – laced with ridicule at a partially sighted Prime Minister – provoked a public backlash.
When it emerged that Mrs Janes had taped the conversation, the suspicion was that she had been put up to it by The Sun and that she had been coached in her questioning.
The strength of opposition is reflected in today's ComRes poll for The Independent on Sunday, in which 60 per cent of people agree that The Sun was unfair to Mr Brown.
Labour insiders claimed the paper's coverage last week had made Mr Brown stronger, because it was so obviously the partisan position of a Cameron-supporting newspaper.
"If The Sun hadn't gone early against us [at Labour conference], then this story would have been more powerful and damaging," said one.
In his Downing Street press conference on Tuesday, Mr Brown gave an assured performance. Yet he misfired slightly by portraying himself as a victim in the row, saying he was a "shy person".
His fortunes continued to improve on Thursday night when Labour won the by-election in Glasgow North East with a majority of 8,111 over the SNP. Mr Brown said it was evidence that voters backed the Government on the economy and Labour could win a fourth election victory next spring.
In his weekly podcast yesterday, Mr Brown looked ahead to Wednesday's Queen's Speech by promising the Government would introduce legislation to ensure Britain had a "bright future". But he cannot be confident that his own future is similarly bright. Winning one skirmish with the Tory-supporting Sun does not mean he can overcome the opposition of the powerful Murdoch press. And a by-election win against the SNP government in Holyrood does not mean the party can turn around the 14-point Tory lead in the polls.
Mr Brown will deliver a speech on future strategy in Afghanistan tomorrow. However, the war is now overwhelmingly unpopular, as the IoS poll shows today. In addition Mr Brown faces the anger of female former ministers over the scrapping of childcare vouchers for all but the poorest families. And questions over his leadership have not gone away. Perhaps the most ominous moment for Mr Brown last week was David Miliband announcing he would not stand for the EU foreign affairs job, despite lobbying from Europe. Mr Miliband said: "I came into politics to serve the people of Britain in Britain. My commitment is to Britain and the Labour Government."