Plots against leadership,

The first signs of internal disquiet towards Brown's policies surfaced as early as May 2008. Brown, in his 2007 budget, his last as Chancellor, abolished the 10% income tax rate for the lowest earners (5.1 million people), increasing their rate to the next highest, 20%. Earners who fell within the 22% tax rate band had their rate reduced to 20%, and tax allowances were also made for over-65s. These measures came into effect in April 2008. The "10p tax rate cut" as it was commonly referred to, was sharply criticized by Frank Field and several other backbenchers. Field also made comments saying that Brown did not seem to be enjoying his job. Health Secretary Alan Johnson believed that Field was motivated primarily by a personal dislike of Brown, and Field later apologized, saying that he had regretted allowing his campaign to "become personal". In the face of protests such as this though, Chancellor Alistair Darling cut the tax rate for 22 million people, and borrowed around £2.7 bn to reimburse those on lower and middle incomes who had suffered.

In the summer of 2008, Brown's leadership was presented with a fresh challenge as a large number of senior MPs openly called for him to resign. This event was dubbed the 'Lancashire Plot', as two backbenchers from North West England urged him to step down and a third questioned his chances of holding on to the Labour Party leadership. Several MPs argued that if Brown did not recover in the polls by early 2009, he should call for a leadership contest. However, certain prominent MPs, such as Jacqui Smith and Bill Rammell, suggested that Brown was the right person to lead Britain through its economic crisis.

A second assault upon Brown's premiership was launched in the autumn of that year, when Siobhain McDonagh, a MP who during her time in office had never voted against the government, spoke of the need for discussion over Brown's position. McDonagh, a junior government whip, was sacked from her role shortly afterwards, on September 12. Whilst McDonagh did not state that she wanted Brown deposed, she implored the Labour party to hold a leadership election. McDonagh spoke of a "huge number" of Labour MPs who wanted a leadership election; her views were somewhat substantiated in the following days when several Labour MPs, including Field, Joan Ryan (who applied, as McDonagh had, for leadership nomination papers, and became the second rebel to be fired from her job), Jim Dowd, Greg Pope, and a string of others who had previously held positions in government, made clear their desire for a contest. In an unrelated incident, 12 backbenchers signed their names to a letter criticizing Brown in Progress magazine. Eric Joyce, one of the MPs who signed this letter, said that Brown's future hinged on his performance at the upcoming Labour party conference.

A Downing Street source responded to these revelations by stating that, "The Blairites have been talking up the idea of loads of ministers resigning. But the best they can come up with is an assistant government whip." Tony Lloyd, chairman of the parliamentary Labour Party, labelled the rebellion a "bit of a sideshow",[108] and Emily Thornberry MP called Brown the "best qualified" to lead Britain through the economic crisis of 2008.[107] The Labour party admitted that it had received letters from a small number of MPs querying why no nomination papers had been released.

In the face of this growing speculation over Brown's future, the majority of his ministers also backed him to lead the party, and two, Harriet Harman and David Miliband, vigorously denied that they were preparing leadership bids. After the shock loss that Labour suffered in the Glasgow East by-election in July, Harman, the deputy leader of the party, suppressed rumours regarding her intentions, saying that Brown was the "solution", not the "problem"; Home Secretary Smith, Justice Secretary Jack Straw, Schools Secretary Ed Balls and Cabinet Office Minister Ed Miliband all re-affirmed their support for Brown. The deputy Prime Minister under Blair, John Prescott, also pledged his support. Foreign Secretary David Miliband was then forced to deny that he was plotting a leadership bid, when on July 30, an article written by him in The Guardian was interpreted by a large number in the media as an attempt to undermine Brown. In the article, Miliband outlined the party's future, but neglected to mention the Prime Minister. Miliband, who had been forced to quell rumours that he would run against Brown in the leadership election of 2007, responded to this by saying that he was confident Brown could lead Labour to victory in the next general election, and that his article was an attack against the fatalism that had dogged the party since the loss of Glasgow-East. Miliband continued to show his support for Brown in the face of the challenge that emerged in September, as did Business Secretary John Hutton, Environment Secretary Hilary Benn, and Chief Whip Geoff Hoon.