Gordon Brown remains the politician most likely to succeed Tony Blair as Labour leader and prime minister.
He can count on significant support within his party, and despite some recent setbacks, he is still the biggest of the Labour beasts eyeing the top job.
Some say every action and every decision Mr Brown makes is with his prime ministerial ambition in mind. They cast him as a brooding plotter, still straining every sinew to achieve his dream, still totally focused on being Mr Blair's successor.
Brown: Still yearning to be PM?
But his fate is hanging on a whole range of ifs and buts. Potential rivals are emerging for the crown. His predictions for the economy are being questioned in some quarters.
Mr Brown's relationship with Mr Blair, meanwhile, is more and more under the spotlight.
Some say the two are barely on speaking terms. Others reject the suggestion, saying their relationship is central to the government's future.
They are said to be split over the euro - with the chancellor less keen on entry than the prime minister (though they seem to be agreed on one thing - joining the currency remains a long way off).
Mr Brown was also reported to be angry that his request to join Labour's National Executive Committee this year was not granted by Mr Blair.
Indeed, the chancellor took what some regarded to be the extraordinary step of making his disappointment known in television interviews.
Mr Brown was born in Glasgow on 20 February 1951, the son of a Church of Scotland Minister in the small Fife town of Kirkcaldy.
At 12, he was canvassing for Labour and by his 20s he was a leading political activist in Scotland.
He achieved a first class degree in history from Edinburgh University, where he went on to complete a PhD.
Mr Brown's early career was spent lecturing, working in television and making a name for himself in the Scottish Labour Party.
His first attempt to enter Westminster, for Edinburgh South in 1979, was thwarted by the present Tory spokesman on foreign affairs, Michael Ancram.
Mr Brown's supporters say Mr Blair broke a pact to allow their man a free run at the leadership
But in 1983, he took Dunfermline East, a new constituency including Rosyth naval base, pit villages and coastal towns.
Entering Westminster, he came to share an office with the newly elected MP for Sedgefield, Tony Blair.
Within four years, Mr Brown had gained his first frontbench post as shadow chief secretary to the Treasury.
He became shadow chancellor under John Smith's leadership in 1992.
And the death of Mr Smith in 1994 led to one of the longest-running sagas of Westminster life over an alleged agreement broken by Mr Blair.
If you don't know the drill by now, it goes like this: Mr Brown's supporters say Mr Blair broke a pact to allow their man a free run at the leadership.
Mr Blair's supporters say such a deal never existed and that their man was a much more likely future prime minister anyway.
Endless newspaper columns have been devoted to the rift. Mr Brown even tried to kill off the story by saying Mr Blair was "his best friend in politics" in an interview last year.
Part of the reason why the speculation persists is that there is another alleged agreement: that Mr Blair will one day stand down in favour of the chancellor.
But if Mr Brown's leadership ambitions were at least temporarily thwarted in 1994, he continued his devotion to politics.
During the 1997 election campaign, he is said to have worked an average of 18 hours a day, six days a week after running on a treadmill for an hour each morning.
This devotion to his career was underlined by a comment by Mr Brown's former girlfriend of five years, Princess Marguerite of Romania, the eldest daughter of ex-King Michael of Romania, who said a relationship with him was "politics, politics, politics".
Some say the setbacks are an indication that Mr Blair is more willing than ever before to take on his chancellor
If that was true then, Mr Brown, who married PR executive Sarah Macaulay in 2000, changed his perspective when the couple were hit by tragedy early in 2002.
Their daughter Jennifer died in Edinburgh Royal Infirmary, 10 days after being born seven weeks prematurely.
A year later, in October 2003, the couple had a son - John - an event which again saw the softer side of the chancellor.
In government, Mr Brown is undoubtedly Mr Blair's most able minister. As chancellor, he has won widespread praise for masterminding Britain's economic stability.
But there have been questions recently over his predictions for growth - subsequently downgraded - and whether the huge increase in borrowing announced in 2002 is sustainable.
Mr Brown has also lost some key battles, notably over student funding and foundation hospitals.
Some say the setbacks are an indication that Mr Blair is more willing than ever before to take on his chancellor.
In the early stages of government, Mr Brown was seen by some commentators as the prime minister's equal, given the green light to plough his own furrow.
The rows within the cabinet over tuition fees and foundation hospitals have changed all that, they say, showing Mr Blair more ready to back other ministers ahead of the chancellor.
And the Brown camp - and the chancellor has a great deal of backing among MPs glad that someone is voicing their concern about public-private partnerships, for instance - complain of briefings against their man from within Downing Street.
As Mr Brown takes centre-stage again for the pre-Budget report, all the talk of rows and rifts will re-emerge.
And while many will be assessing his economic predictions, there will also be a significant number of people wondering how his statement will affect his political future.