As the Tories tear themselves apart, who is keeping an eye on the Government?

Nick Morrison looks at how the Opposition's failings are giving Tony Blair a free ride - and where the Conservatives go from here.

SPOT the difference: two governments, both riven by internal dissent, both hit by scandal, both having lost the trust of the electorate, both failing to improve public services, one heading for electoral calamity, the other maintaining a comfortable lead in the opinion polls and on course for another landslide victory.

There may be many reasons why Tony Blair still holds a winning hand while John Major was a busted flush. It may be something to do with charisma; it may be that apathy creates a reluctance to disturb the status quo. But there is one thing Major had that Blair doesn't: an effective opposition.

When the Major government was beset by divisions over Europe, crippled by an endless stream of financial and sexual scandals and discredited over its withdrawal from the Exchange Rate Mechanism, it was harried by a resurgent Labour Party, ready to probe every weakness, prod every open sore, pick every scab until it bled again.

But while Blair may have split his party over Iraq, been tainted by the death of David Kelly and led us into a war under false pretences, the Tories have spent the summer agonising over who is going to lead them to defeat in the next election. They have no more worried the Government than a gnat worries a crocodile.

And the result has been to produce a Government which must now believe it can get away with anything. After all, if there is no one to question what you are doing, there is no need to justify what you are doing.

So it is that Tony Blair can claim he had nothing to do with the naming of David Kelly, before he was revealed to have been present at the relevant meeting. So it is that Gordon Brown can hike up our taxes and we still don't see our hospitals and schools improving. So it is that David Blunkett can criticise the BBC for exposing racism in the police, while chief constables make him look a fool by admitting there is a problem. And nobody bats an eyelid.

According to the latest opinion poll, Labour is leading the Tories by five per cent and if a general election were called tomorrow, it would have another majority of 160 or more. It seems that even if the Government is no good, it can still do no wrong.

And while it is clear that the Tories are not being an effective Opposition, more glaring still is that IDS has been punching well below his somewhat trim weight. If his replacement were to be a heavy hitter, such as Michael Howard, they would certainly give Blair more cause for concern, although it doesn't mean they would be more popular with the electorate.

But if it is very hard for a divided party to be an effective Opposition, this situation will not have been improved by the leadership fiasco. Activists in the country are hardly likely to become enamoured of the Parliamentary party now that their choice of leader has been overturned.

The lesson of what happens to a divided party was learnt only too well by Labour in the 1980s. While Labour fought its ideological battles over cruise missiles and Europe, Margaret Thatcher happily notched up two landslides. It was only when Labour managed to unite, even if it was largely a cosmetic exercise, that the party was able to mount an effective challenge.

The danger for the Tories now is not that Blair will go on to match Thatcher's electoral record, for that seems almost a foregone conclusion, but that the Conservatives will be spent as a credible alternative government. True, this was the same fear among Labour supporters during the dark days of the 1980s, and the party not only survived but became stronger than ever before, but the Tories do not seem to have moved on since 1997. If anything, they have gone backwards.

Until 1997, only one Tory leader of the last 100 years had not gone on to become prime minister, Austen Chamberlain. Then along came William Hague, followed by IDS, and chances are his successor will join this list of ignominy. There must be some asking if we will ever see another Tory prime minister.

And while the Tories as a whole have failed to present an effective challenge, it is in their choice of leader that the failure is most apparent, underlined by the fact that there have been some successes on the Opposition front bench, notably Michael Howard and Oliver Letwin. Whatever the merits of the lieutenants, if the general is not up to scratch it's very hard to vanquish your opponent.

Notably, the last four Tory leaders have been outsiders, from Margaret Thatcher onwards, as the party ignored the claims of the favourites, either too tarnished by the past or having made too many enemies. But, Thatcher apart, this preference for the underdog has not done them much good.

John Major may have won in 1992, but he was still surfing a tide of goodwill which swiftly evaporated once the economy went out of control, leaving him to spend the next five years in a state of seemingly permanent misery. Hague may have been more than an intellectual match for Blair, but he never managed to convince the electorate to take him seriously, at least not until he appeared on Have I Got News For You? And as for Iain Duncan Smith, a selling point that no one has heard of you is hardly likely to bring success. By the end this charisma-free cut-out made John Major look like a titan.

It may be too harsh to blame individuals. Both Hague and IDS were always onto a loser, maybe we were so fed up of the Tories that Major didn't stand much of a chance either, and the best the next Tory leader can look forward to is a long stretch in Opposition.

But the real risk is not that the Conservatives will never again occupy Number Ten; it is that everyone will stop believing that they will. For if the Government does not think it will lose, then it has no incentive to keep on its toes.

It was Napoleon who said that what he most looked for in his generals was luck, and Blair has had the good fortune of facing three Tory leaders who made him look like a giant. But it was when Napoleon started to believe he was invincible that it all started to go wrong. It may be that Blair's good fortune turns out to be a double-edged sword.