By Nick Assinder
Political Correspondent, BBC News website
We have been here three times before, but the Tories have a new leader promising to take on Tony Blair and lead his party to election victory - and this time, they insist, it will be different.
After one of the speediest political rises in recent history, David Cameron has been elected as the fourth opposition leader to tackle that task since John Major was defeated in 1997.
Cameron plans to be different
None of them managed to make the longed-for breakthrough but Tory members and MPs believe they are onto something new and different with Mr Cameron.
After starting the contest from virtually nowhere, and with little parliamentary experience under his belt, Mr Cameron raced past all comers, including the original favourite, David Davis, to a decisive victory by more than two to one.
And it is the size of the victory, far more than the victory itself, that has given him a greater opportunity than any of his predecessors in opposition to complete his task.
Not only did he win with the overwhelming support of grassroots Tories, but he has a similar level of support on his backbenches in the Commons.
Quality of life
And that gives him a powerful mandate to do with the opposition pretty much whatever he likes.
And what he appears to like is a leftish "modern, compassionate Conservatism" - the first leader to be selected from that wing of the party.
He started to map out the direction he intends to lead the opposition during his acceptance speech, talking in broad terms about changing the way the Tory party looks, feels, thinks and behaves.
Cameron raced past former favourite
In specifics, he spoke about more women and non-white male candidates and an end to the "Punch and Judy" politics with all the jeering and name calling that goes with it.
Once again he promised to support the government if he agreed with it, and not, presumably, just as a tactic to further isolate Tony Blair from his restless backbenchers - although it may well have that effect.
He also highlighted specific areas for action on areas from public service reform to improving the quality of life.
He symbolically moved on from Thatcherism by declaring there WAS such a thing as society, "it's just not the same thing as the state".
That is Labour's mistake, he implied, believing the state could provide the services and society Britain needs and deserves.
And he offered a couple of hints on policies such as making police chiefs accountable and offering a national school leavers' service.
Cameron expects to face Brown at election
But the biggest thing he appears to offer the Tories, and the thing that seems to have shot him to the top job, is a belief they have the sort of modern, in-touch, pragmatic and charismatic leader that did such wonders for New Labour.
He dismisses the "Blair lite" tag, with good reason as he believes the prime minister's era is over.
Instead, he expects to be facing Gordon Brown in the run up to the general election in around four years' time.
And, as he said himself, he believes there is "something in the air" this time which will pilot him into 10 Downing Street.
And it may well be that the political tectonic plates are moving, that voters are ready to look away from Labour and, finally back towards the Tories.
If he has come into office when the political stars are aligned just right, and he is canny enough to follow the destiny they offer him, he might just pull it off.
For now, however, he faces the nerve-wracking prospect of his first prime minister's question time on Wednesday - although his MPs will give him some leeway for a couple of weeks or so on that one.
And he will have to get on with forging a shadow cabinet in his own image and forging some distinctive policies to regain the vital middle ground which the Tories have lost to New Labour.