CHRIS FISHER, EDP Political Editor The three main parties will go into the parliamentary summer recess tomorrow in radically different moods, and the happiest - by quite a margin - is the governing one.

CHRIS FISHER, EDP Political Editor

The three main parties will go into the parliamentary summer recess tomorrow in radically different moods, and the happiest - by quite a margin - is the governing one.

Gordon Brown probably hasn't been mistaken for a big ray of sunshine many times in his life, but all of a sudden there is a warm glow at the top of the Labour Party.

The Tories by contrast are blue in more than one sense. Dark clouds have moved over them, and they are raining on David Cameron's parades. And the Liberal Democrats are neither one thing nor the other; dissatisfaction with the lack of electoral progress under Sir Menzies Campbell continues to simmer, but it is accompanied by relief that the Conservatives are now just as troubled as they are - and arguably more so.

Some in the Labour camp are not merely very pleased but almost euphoric. Commenting on last week's by-election results in Southall and Sedgefield, a Labour aide commented: “This was the moment we knew the next election was in the bag.” Really? The election doesn't have to come until June 2010, and hardly anyone really expects that it will be held before next spring. And if the political mood can change substantially in just a few days, as it just has - confirming that a week is a long time in politics - it can undergo a profound metamorphosis over a few months, let alone a couple of years.

The by-elections were significant, however. For a start, they confirmed that there has been a shift in electoral opinion since Mr Brown replaced Tony Blair as prime minister. He has pleasantly surprised rather a lot of people with his early decisions and scene-setting, and that was reflected in the by-election results as well as recent opinion polls. Four of the latter in the past 10 days have been consistent in giving Labour a six-seven point lead over the Tories. Such a margin would be enough to give Mr Brown a big Commons majority.

By-elections can, moreover, generate and alter opinion as well as reflect it. The Southall and Sedgefield contests made Labour look more solid and durable, and they also let quite a lot of air out of Mr Cameron's balloon. The Tories had hoped to retain second place in Sedgefield and at least regain that position in Southall. Early in the campaign they even started to let themselves think that a sensational victory was possible in the west London seat.

That looks silly now. And Mr Cameron has started to come under fire from a few of the people - Lord Tebbit included - who have never liked his strategy for rebranding and repositioning their party. They have been keeping their heads down while the Tories were ahead in the opinion polls and Mr Cameron appeared to have a reasonably good chance of winning power. But now the picture looks different, and the self-imposed gags are coming off.

Mr Cameron has reacted by saying he has no intention of retreating to “the comfort zone” of the values and messages that used to be associated with the Conservatives. And he has a point, of course. The ideas he is being asked to readopt didn't exactly prove an electoral hit in 1997. Or 2001. Or even in 2005 when Mr Blair had the Iraq millstone round his neck. Why would they help the Conservatives next time?

There is some comfort for the Tories in the fact that the Liberal Democrats had disappointing results in the by-elections. They kept second place in Southall and won that position in Sedgefield. But the Lib Dems have had so many 'shock' victories in parliamentary by-elections - the last one coming in Dunfermline and West Fife last year - that they have ceased to shock. They are almost expected, and by their standards their results last week were damp squibs.

This leaves the 'Ming question' very decidedly unresolved. The results weren't bad enough to trigger an immediate move to replace the Lib Dem leader, but they weren't good enough to end the muttering in the ranks.

It is not only the by-elections and the opinion polls that have put smiles back on Labour faces. There is also the decision by the Crown Prosecution Service not to charge anyone after the Scotland Yard inquiries into the 'loans for honours' allegations - a decision that in some quarters has caused almost as much head-scratching as Lord Hutton's conclusions after the inquiry into the circumstances leading to the death of David Kelly.

How can it all have led to nothing? Well, having a strong suspicion that illegal political skulduggery has been taking place is not the same thing as having enough hard evidence to convince a court of law.

Hopes of prosecutions crashed when the CPS was advised that the police needed evidence of “unambiguous agreement” by which Labour donors gave money only on the explicit assurance that they would be honoured in reward.

There should be no great surprise that that evidence isn't there. Political operators with the nous to reach and remain at No 10 aren't amateurs who are going to leave their fingerprints everywhere. It was a reasonable assumption from the start that any arrangement would have been reached on a less than definite 'maybe you will have a good chance of an honour' basis and that nothing would have been put in writing.

Assistant commissioner John Yates should not be adversely criticised in my opinion. Once an inquiry was launched - as it should have been given the seriousness of the allegations - he had to be seen to be looking under every stone he could find. Otherwise he would have faced claims that he was protecting the powerful.

A bad smell is left, of course. So why did Labour take loans instead of gifts? We may never get a convincing answer to that that is honourable. But Mr Blair and the party he led seem to be off the hook. And his successor is possibly on his way to a general election victory.