A week is a long time in politics," Harold Wilson once famously remarked. Just when things were looking up for British Prime Minister Gordon Brown - he was credited with effectively dealing with a number of crises in summer, his Labour Party was leading in the polls and he had a very good party conference - the Opposition Conservatives caught up in the polls after their very successful party conference and Mr Brown shot himself in the foot after his somewhat humiliating decision not to call a snap general election after all.

After weeks of speculation and spin about an early election, Mr Brown backed down from calling a general election after an opinion poll revealed that the Conservatives were leading Labour by six points in a number of key marginal seats. If the poll was accurate and an election were held the result would have produced a hung Parliament, with a Conservative relative majority. This would not have been a particularly good result for the Tories but it would have been a disastrous one for Labour which would have ended up in Opposition after 10 years in power.

Mr Brown was certainly not going to risk such a possibility; he has, after all, been waiting to move into 10 Downing Street for 13 years. However, his decision to backtrack on an early election led to accusations of weakness and indecision from the Conservatives. The Prime Minister, on the other hand, seemed to have the backing of his party and one Labour MP told Sky News that the fact that Mr Brown had decided not to call an election was not a sign of indecision - he took a definite decision not to call an election, which is his prerogative.

Nonetheless, Mr Brown came out very badly from this whole episode. He was not obliged to call an early election as he was a central figure in the 2005 election, which gave his party a clear mandate to govern. Everyone knew Mr Brown would replace Tony Blair a couple of years after the last election - one of the Conservative Party's slogans in the 2005 poll was "Vote Blair. Get Brown." Many were not convinced by Mr Brown's claim that he chose not to go to the polls because he wanted to present a clear vision to the electorate on how he intends to change Britain. If that were the case, why did he allow weeks of speculation about an early election?

What has emerged after last week's change in fortunes for Mr Brown is that Labour's dominance of Britain's political scene is finally facing a serious challenge from the Conservatives for the first time in 10 years. Under Mr Blair, Labour won three consecutive general elections, the first two by a landslide and the third with a very comfortable majority. During his time as Labour leader and Prime Minister Mr Blair faced five different Conservative Party leaders, none of whom, except perhaps for David Cameron, the current leader, were any match for him.

Today Mr Blair has been succeeded by Mr Brown, who faces a serious challenge from Mr Cameron and his invigorated Conservatives. Mr Cameron's hour-long speech from memory at the Conservative Party conference in Blackpool was very well received. Alistair Darling, the Chancellor of the Exchequer, remarked: "One speech doesn't change anything." However, polls taken after the speech showed a sharp boost for the Conservatives - one even showed the party neck and neck with Labour.

Furthermore, proposals at the Conservative conference by Shadow Chancellor George Osborne certainly struck a chord with the electorate. Mr Osborne said a future Conservative government would abolish inheritance tax except for millionaires as well as stamp duty for first-time home-buyers.

So popular were these proposals that the government announced, in its Budget on Tuesday, that the threshold at which inheritance tax is paid is now being raised from £300,000 to £600,000 for married couples. Mr Osborne's reaction was somewhat predictable: "Let there be no doubt who is winning the battle of ideas. He (Gordon Brown) should have called that election and let us give the Budget."

Mr Cameron's focus on core issues such as health, education, the environment and crime has also proved popular, as he seems to be in touch with the ordinary concerns of people. Such a strategy is in marked contrast to the one adopted by past Conservative leaders, who seemed to be obsessed with issues such as immigration, Europe and tax cuts.

So it looks like the Conservatives are finally putting up a serious challenge to Labour and have learnt a thing or two from past mistakes. One thing looks certain - politics in the UK has become competitive again and Labour can no longer take its dominance of the political scene for granted. The big winners here are the British people who will have a real choice at the next election and who stand to gain from a more serious level of political debate.

There is bound to be a key battle for ideas in crucial areas such as health, education, the environment and crime and this certainly a good thing. I will not write off Gordon Brown as he has a lot to offer and has proved his leadership skills on many occasions. However, I believe Mr Cameron has a decent chance of winning the next election which will probably be held in 2009 - although two years is a very long time in politics. The electorate will have to decide whether Mr Brown or Mr Cameron is the right person to bring about change in Britain. That is the crucial question, so both leaders have a lot of work to do.