WI: Portillo wins the Conservative leadership in 2001

He only missed out on the final round by a single vote (Clarke - 59, Smith - 54, Portillo - 53), so if one more MP had voted for Portillo rather than IDS, Portillo would have made the final round instead. I imagine that Portillo would have been able to defeat Clarke and become Conservative leader.

How would a Portillo leadership have changed the course of recent British political history?

IMO, the Tories would have done better in 2005 than in OTL by maybe 20-25 seats, perhaps even trimming the Labour majority into single digits. At times during the 2001-2005 parliament, the Conservatives would have had solid and sustained leads in the polls. Portillo was about the only high-ranking Tory at that time who matched Blair's charisma and political skills.
 
I can't remember the exact figure, though I have mentioned it before, but it would only take about 25,000 votes in the right seats to force a hung parliament in 2005. I think Portillo would easily have managed that, generating much less opposition than Howard did (giving disaffected Labour voters less reason to actually turn out and vote). Actually winning a majority for the Conservatives would require a bigger shift (I think around 300,000), but is not impossible.

On the other hand, when you consider some of the current ructions that Cameron is having, Portillo might have had internal party problems. He would have supported the government over scrapping Clause 28 and introducing civil partnerships (maybe even advocated going further), at a time when most Tories (including Cameron) were implacably opposed.
 
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