It was tempting last year to imagine Labour had the next election in the bag.

The Government鈥檚 economic strategy appeared to be a failure. Instead of enjoying economic growth, the country apparently entered a double-dip recession at the start of 2012.

George Osborne, the Chancellor, saw his reputation plummet after a disastrous Budget which gave us the 鈥済ranny tax鈥 鈥 the abolition of the 鈥渁ge-related allowance鈥, effectively a tax-break on pensions 鈥 as well as an unpopular increase in petrol duty. And opinion polls showed Labour well in the lead.

Labour MPs certainly had a spring in their step as they contemplated the prospect of party leader Ed Miliband entering Downing Street after the next election.

But the mood has changed. It turned out that the economic figures were wrong and the 海角视频 did not suffer a second recession last year after all (although Labour鈥檚 charge that the economy had 鈥渇latlined鈥 was correct 鈥 growth was zero rather than negative).

George Osborne鈥檚 sins were forgiven, by his own side at least, following a series of U-turns over many of his budget errors.

And while economic growth remains slow 鈥 with the International Monetary Fund predicting growth of 0.9 per cent this year 鈥 the economy is at least moving in the right direction.

This has allowed the Government to claim the economy is moving from 鈥渞escue to recovery鈥.

To some extent, how voters feel about the economy is more important than what the figures show. And Tories believe that voters are beginning to feel more optimistic about the future. Opinion polls suggest that Labour鈥檚 lead over the Conservatives is narrowing.

From around April 2012 most opinion polls put Labour at least 10 points ahead of the Tories.

But that has changed. The latest ComRes poll put the Conservatives on 34 per cent of the vote, with Labour on 37 per cent, the Lib Dems on 10 per cent and 海角视频IP on 12 per cent. That鈥檚 a Labour lead of three per cent 鈥 the lowest ComRes has shown since last September.

Recent polls from YouGov, another leading polling organisation, gave Labour a lead of between three and seven per cent.

And a poll by ICM, published in mid-July, found that Labour and the Conservatives were tied, each backed by 36 per cent of voters.

Every other poll has given Labour some sort of lead. And in any case, opinion polls may not be a good guide to the precise share of the vote each party would receive in a real election.

But there has been a clear trend over a period of time for the gap between the parties to fall.

One potential explanation for this is that support for 海角视频IP is beginning to ebb away (although many polls still show it is more popular than the Lib Dems).

海角视频IP leader Nigel Farage likes to point out that some of the party鈥檚 support comes from former Labour voters, not Tories 鈥 a point echoed by Conservative chairman Grant Shapps.

But in practice, many Farage fans are indeed former Conservative voters. If they are returning to the Tory fold it may help to explain why the Conservatives are closing on Labour. This would actually suggest that Ed Miliband鈥檚 lead was never quite as healthy as it looked even when Labour was roaring ahead.

Some of 海角视频IP鈥檚 support comes from people who are fed up with the major parties and want to send them a message. In other words, it鈥檚 a repository for protest votes. And while that can lead to success in by-elections, European elections and opinion polls, protest voters tend to return to one of the main parties when a general election comes around.

So if Labour鈥檚 lead in opinion polls was partly due to the growing popularity of 海角视频IP, it suggests that lead may always have been exaggerated a little.

But there may be other reasons for the revival of Tory fortunes. The economy, as mentioned, could be one.

The party鈥檚 tough stand on benefits, although highly controversial and bitterly opposed by campaigners who argue it victimises some of the most vulnerable people in society for political purposes, is believed by the Tories to be a vote winner.

The focus on failings in the NHS may also be having an effect.

Health Secretary Jeremy Hunt was condemned by Labour MPs when he argued, in a personal attack on Labour Shadow Health Secretary Andy Burnham, that the previous government鈥檚 focus on targets had damaged patient care.

But while Conservatives may never succeed in David Cameron鈥檚 aim of replacing Labour as 鈥渢he party of the NHS鈥, they might at least succeed in casting doubt on Labour鈥檚 competency when it comes to running the health service 鈥 taking away, or undermining, one of the positive reasons for voting Labour, even if they cannot transform it into a positive reason for voting Conservative instead.

The truth is that we can never know for sure why voting intentions change.

As YouGov鈥檚 Anthony Wells explains, on his blog ukpollingreport.co.uk, simply asking people doesn鈥檛 work.

He wrote: 鈥淚f you ask people who gave a different answer three or four months ago if they鈥檝e changed their mind many won鈥檛 realise they have.

鈥淚f you ask why to those who have consciously changed their mind you get lots of don鈥檛 knows, general grumbles and some reasons that may be genuine causes, or may be post-hoc rationalisations for complex decisions we probably don鈥檛 even understand ourselves.鈥

There鈥檚 also a tendency to assume poll results back up our personal political views. Supporters of a referendum on Europe might imagine voters are returning to the Conservative Party because David Cameron has offered one, for example.

One interesting result to come out of the latest ComRes polling is that voters don鈥檛 much like coalition government, with 73 per cent saying they 鈥減refer one party to win an outright majority at the 2015 general election than have another coalition government.鈥

And asked to look back at the 2010 election, 29 per cent agreed that 鈥淏ritain is better off with a coalition government than it would have been if either the Conservatives or Labour had won the last General Election鈥 鈥 with 57 per cent disagreeing.

This could potentially spell bad news for the Lib Dems. If a hung Parliament looks likely, the two major parties will be able to argue that a vote for Nick Clegg is a vote for another coalition (even though the way the vote is shared out between Labour and the Tories is the most important factor 鈥 the Lib Dem share of the vote rose by only one per cent in 2010).

It would be an historic victory if David Cameron won an outright majority in 2015 鈥 and it鈥檚 still hard to see how he could. He鈥檇 need to win more than the 36 per cent of the vote the Tories received in 2010. And no sitting Prime Minister has increased their party鈥檚 share of the vote since 1974. Even Margaret Thatcher in the 1983 election, after the Falklands War, saw her share fall by 1.5 per cent from the 1979 election.

The party conference season this summer will be crucial in determining whether Labour can regain momentum and end Tory dreams of making history.