The bit about the budget surplus in '97? Completely irrelevant. Budget surplus is just about this year's net borrowing requirement (and the fool Osborne is pissing £2billion a week up the wall on that front)
National debt - the actually important measure - was 47% of GDP when Major left office, and 36% when Brown left. Growth and repayment had got it down below that, but then there was investment; the debt as a percentage of GDP grew, but in ways designed to recoup the investment.
Then, in the 2008/09 financial year, a large amount of financial securities turned out to be so much pig flatulence and titanic quantities of debt got defaulted on. Now, lending and borrowing is how money is created (commodity standards like gold and silver are a myth: money was first created by extending credit for goods and services and the first writing systems were invented to keep track of it, looking up the relevant scholarship is left as an exercise for the reader) so when a load of borrowing and lending collapses, suddenly there's a lot less money. Contractions in the money supply are what causes recessions (look up Paul Krugman's babysitting circle analogy to understand why, it's really clear and simple) and the whole thing was caused by unregulated banking.
Labour's response, correctly, was to dig into government borrowing - putting debt as a percentage of GDP up sharply, because they increased borrowing while the economy contracted) and the graph of UK growth reversed. And then from Q2/3 of 2010, with the fool Osborne at the helm, it went flat with occasional dips. Recession. It took them less than ten years to undo Brown's ten years of good work. What he's doing, in economic terms, is the equivalent of slamming the brakes on with a hill to climb.
Result: from 36% of GDP when they took office to 91% estimated for this fiscal year. After having killed off an improving trend, they've shrunk the economy and added to debt.
Summary: deficit is not debt, and deficit is not a useful measure of government performance (and that makes it all the more hilarious that the economically-illiterate tories are relying on it, because they're failing by THAT measure too). Debt is a useful measure of performance, relative to national wealth, and on that score Brown was a success and Osborne is so far below him in the league tables he's barely playing the same bloody sport.
(comforting note: we've had national debt at levels like 600% of GDP and the nation didn't implode. It's not the size of the debt, it's your ability to service it that counts. Whoops. The market's doubting that, too, hence the downgrade in our credit rating.)