A fairly simple challenge: With a POD of May the 2nd 1997, have the Conservatives win the 2001 general election (or 2002, if Blair decides to wait until Parliament runs its course).
 
Blair waits till 2002 and tries to do a Maggie T great wartime leader impression. Labour big up the war on terror. The Tories surprise everyone by backing the Stop the War Coalition. This erodes Labour support in some rather safe Labour voting demographics like the young. At just the right time the dodgy dossier is revealed and the Labour campaign never recovers. It's not going to be a landslide but it's just enough to oust Blair and co.
 
OTL, Blair & Labour bled support constantly from '97 to'15 as their traditional support slowly realised how far he and his cronies had taken their party from what they believed in.
ATL, make them less naive.
 
Blair waits till 2002 and tries to do a Maggie T great wartime leader impression. Labour big up the war on terror. The Tories surprise everyone by backing the Stop the War Coalition. This erodes Labour support in some rather safe Labour voting demographics like the young. At just the right time the dodgy dossier is revealed and the Labour campaign never recovers. It's not going to be a landslide but it's just enough to oust Blair and co.
I'm not sure about this - aside from Ken Clarke (under whom the Tories certainly wouldn't win back power, given the infighting that his leadership would cause), I can't see any Conservative leader opposing the War on Terror pre-Iraq. And, speaking of which, prior to Iraq the War on Terror was on the whole popular across the Western world, who felt a large degree of sympathy with the US, and so I'd see taking a stance against the War in Afghanistan backfiring more than anything else.
 
The 2000 Fuel Protests could get really out of hand coupled with a worse Ecclestone scandal. But you would need an amazing Tory leader to unify and detoxify the party in so short a time.
Personally, I think that Michael Howard would've been the best candidate in 1997 to achieve that. So perhaps the Hague-Howard Pact holding could be an appropriate point of divergence?

I think that the uplift in fortunes for the Tories between 1945 and 1950 serves as a stark contrast to a similar period between 1997 and 2001 - in both cases, the Conservatives lost to Labour in landslides, only in the first instance Churchill rebound, slashed Attlee's majority drastically in 1950 before returning to government the following year, while in the second Hague only achieved a net gain of one seat - so what was different?
 
It’s possible with some sort of crisis but the Blair government was incredibly effective in the early period. 2001 was a landslide win for labour (almost as big as 1997) because of that.

You’d need some sort of crisis (likely multiple) being badly mishandled by the government and for the Tories to somehow get their case together. Stopping the landslide is one thing - but a conservative victory is difficult.
 
The best (or perhaps only) way that I see this happening is if Labour suffer a massive split over something that allows the Tories to come through the middle. But for that, you'd need a big issue to ignite a civil war, and there wasn't much of that back in that parliament. So basically some huge terror attack on the scale of 9/11 happens and the consequences of that lead to one side of Labour falling out from the other- or there is some other freak accident which creates a crisis.
 
Short of ASBish events, I just can't see it. We are talking about Labour (after 18 years in the wilderness) pissing away everything in just four years in power and having Blair Sideshow-Bob into rakes, while the Tories get their act together - which would require them to figure out what is their act in the first place. When a governing party loses an election, especially one that regards itself as a natural party of government, the notion of honest self-analysis to move forward is probably the furthest thing from its hive mind. It's not some kind of accident, or tweak of history, that gave the Tories a Hague-IDS-Howard demarche to nowhere. That's pretty much the personification of the stages of grief of a political party losing power and relevance.
 
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