The British-English and Irish-English political phrase Portillo moment designates the defeat of a high-profile Member of Parliament in a seat thought to be safe—a defeat, especially in a general election, indicating a significant political change.

This phrase occurs, for example, in An anti-Tory landslide points to the end of an era in British politics, published in The Guardian (London and Manchester, England) of Tuesday 7^th May 2024 [Opinion section: page 2, column 2]:

Local elections are not known for producing “Portillo moments”. But the defeat of the Conservative West Midlands mayor, Andy Street, announced late on Saturday, undoubtedly encapsulated a sense of tectonic plates inexorably shifting in Labour’s favour. A locally popular and avowedly non-ideological figure, Mr Street had done his best to distance himself from the Tory brand. But there was no escape from the determinedly anti-Conservative mood abroad the nation.

The phrase Portillo moment originated in the declaration of the result for the Enfield Southgate constituency in the early hours of Friday 2^nd May 1997: the Labour candidate, Stephen Twigg (born 1966), defeated the sitting MP, the Conservative politician Michael Portillo (born 1953), Secretary of State for Defence. This shock announcement was seen as emblematic of the Conservative defeat in the 1997 general election.

The earliest occurrences that I have found of the phrase Portillo moment applied to Michael Portillo’s 1997 defeat are as follows, in chronological order:

1-: From So where were you when Portillo fell?, by Miles Kington, published in The Independent (London, England) of Monday 12^th May 1997 [No. 3,294, page 15, column 5]:

Even though the election was nearly two weeks ago, […] people I have not seen since then are still coming up and saying “Great, wasn’t it?” They never say what they are talking about, but I always know. They don’t mean the Eurovision Song Contest or the welcome arrival of rain. They mean the election night.
[…]
My interlocutors then usually go on to pick out a particular moment for praise, usually the moment when Michael Portillo’s defeat was announced.
“Did you see the moment when Portillo realised he had been beaten?” is the usual remark, varied with “Did you see the moment when young what’s-his-name, the Labour bloke, Twigg, realised that he’d actually beaten Portillo?”
Close runners-up to this are “Did you see Mellor losing his rag?” and “Did you see Neil Hamilton get his comeuppance?” but it is definitely the Portillo moment that gets the prize. You can see why, in a way. Here was the leading contender for the Tory leadership being ousted from the contest, rather like the chief suspect being killed off in the last-but-one act, so you suddenly have to revise all your ideas of the denouement.

2-: From Words we never thought we’d write: In praise of Portillo, by John Sweeney, published in The Observer (London, England) of Sunday 12^th October 1997 [No. 10,748, page 21, column 1]:

Last Thursday evening he [i.e., Michael Portillo] captured the party’s soul.
He reminded the packed fringe meeting that he lost Southgate on a 17 per cent swing: he had no right to lecture anyone. Then he analysed what the Tories had done wrong, where they had been hopelessly out of touch on landmines and arms sales and corruption: ‘Sleaze disgraced us in the eyes of the public.’
True.
He may have spent the summer reading A la Recherche du Temps Perdu—it’s a book about a cake—but he is still a politician.
The first questioner asked whether he supported the party masses in their bid for one man, one vote, for the Tory leadership. He smiled and recalled the Portillo moment on the night of 1 May: ‘That night Jeremy Paxman asked me some impossible question and I had a stroke of inspiration. I said that I was no longer a member of the Cabinet or even an MP. I don’t have to answer the question. Sorry, Jeremy.’
And then he sat down. A wave of laughter swept the audience when they realised that he wasn’t going to answer the question.

3-: From an interview of the Pakistani-British political activist, author and journalist Tariq Ali (born 1943)—interview by Jay Rayner, published in The Observer (London, England) of Sunday 4^th October 1998 [No. 10,799; Review section: page 5, column 5]:

‘Look where this Government is leading us. There are obsessions with centralisation, with institutions, a break from social democracy.’
So would he rather the Conservatives were still in power? ‘No, I wouldn’t want that. It was critically important that the Tories were voted out. I shared the Portillo moment.’ But still, he says, New Labour is a vast disappointment.

The earliest transferred uses of the phrase Portillo moment that I have found are as follows, in chronological order:

1-: From the column Inside the campaign, by Jonathan Freedland, published in The Guardian (London and Manchester, England) of Wednesday 6^th June 2001 [page 18, column 3]:

This time four years ago, […] on the eve of the 1997 general election, activists could be seen handing out not the usual party literature but a photocopy of a newspaper cutting.
The item was from the Observer, a pre-election guide detailing exactly which Conservative luminaries were vulnerable to defeat—so long as anti-Tory voters got their act together and backed the candidate best placed to win. In Enfield Southgate, canvassers merely had to hand out the Observer item to prove how the local MP could be beaten: no extra commentary was needed. Early on May 2, the result was on television for all to see: Michael Portillo was out.
This time […] there will, no doubt, be a frisson of delight—almost a Portillo moment—if Michael Howard goes down in Folkestone and Hythe. The much expected ejection of Oliver Letwin from Dorset West will raise a cheer in anti-Tory households. But nothing can compare to an 18-year Conservative regime crumbling before your very eyes.

2 & 3-: From an account of the 2001 general election night, by Euan Ferguson, published in The Observer (London, England) of Sunday 10^th June 2001 [No. 10,939]:

2-: [Election 2001 section: page 2, column 5]:

Results swarmed in with a thumping predictability […]. Labour hold, but turnout down 9 per cent. Labour hold, but turnout down 12 per cent. When Stephen Twigg gave his gee-shucks speech again in Enfield Southgate there were rare heartfelt cheers, but there was no Michael Portillo moment.

3-: [Election 2001 section: page 3, column 3]:

The decent Lib Dems actually wept in triumph when they took Tony Benn’s old seat at Chesterfield; it was their Portillo moment (and, appropriately enough, the next seat to be declared was Enfield Southgate.)

4-: From the column Buzz words, published in The Guardian (London and Manchester, England) of Saturday 16^th June 2001 [The Editor section: page 4, column 1]:

Gloria Gaynor of Hartlepool
The name given to Mandelson after the I Will Survive-style speech he gave at his Hartlepool count, the “Portillo moment” of this year’s election