Is zero the most powerful number in politics?

Gavan Reilly

In Politics by Numbers, broadcaster, author and spreadsheet stan Gavan Reilly takes a data deep dive into a political point of the week.    

ECONOMICS IS SUPPOSED to work on a fundamental premise: that in any given scenario, people will act rationally to further their own interests.

But within the branch of behavioural economics, there is a number that tends to turn this assumption on its head. It’s zero: when things are free, the usual expectations of how people react tend to go out the window.  

Here’s an example: lots of young people are settling back into college life now, and plenty of part-time salespeople will be on campuses trying to promote energy drinks. If you were going about your business, and you passed someone in a quadrangle or concourse trying to sell you a can of it for €2, would you take it? How about €1.50, or €1? Maybe 50c would be enough to get you to try a random drink from a stranger? No. But if someone offered it to you for free – even if you weren’t thirsty, and had just finished a coffee – would you take it?  

Zero can be a magic number when it comes to changing how people behave. And, in politics, it can sometimes send people in all sorts of unexpected directions. For proof of this, you only need to look at the last few weeks of The Traitors.

When there’s no evidence, ‘evidence’ is created

It’s easy to watch the goings-on in Slane Castle with the benefit of an omnipotent eye, knowing who is and isn’t a Traitor, and giggling as the Faithful run headfirst down blind alleys chasing wild geese and utterly convinced of their correctness. (I’m half-expecting a TD to put down some parliamentary questions inquiring about the quality of military police investigations.) 

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But the true genius of the format, and what makes the series to be such a compelling watch, is how it makes contestants fill a void almost by inventing evidence based on nothing more than idle speculation and gut hunches. Two people have different recollections of a fleeting conversation that didn’t even happen that day? A survivor didn’t respond to someone else’s murder in the precise way you’d expect them to? Someone who was banjaxed tired during a challenge, wasn’t able to fully devote themselves to harvesting the biggest cash prize for the team? Guilty! Banish them! 

There is often zero concrete evidence that someone is actually a secret Traitor intent on sewing drama and division within the group. But it doesn’t stop people latching onto theories and swarming like lemmings onto an innocent bystander. Six Faithful players were banished by their fellow contestants after heated roundtable debates and sidebar conniving – none of whom, by definition, were actually Traitors to begin with. Six scalps, zero evidence.

How does this relate to politics? Well, it’s also easy for a narrative to take hold in Leinster House without there being much evidence to sustain it.

A referendum to stop a sale to nobody 

Dozens of parliamentary questions have been tabled in recent years – though none so far in 2026 – about the idea of holding a referendum on the ownership of Ireland’s water utilities. There’s a reasonable policy reason for doing this: anyone with experience of living in an English city will be familiar with the ugly inefficiency of private water companies, which Andy Burnham is now actively trying to undo with a programme of renationalising household supplies. 

But the real motivation for a referendum in Ireland is not the experience in England – it’s the simple fear that the experience of water charges in Ireland would somehow give a private bidder the motivation to step in and simply buy the Irish network (leaky Victorian pipes and all). Anyone who paid much attention to austerity-era Irish politics will remember how bitterly some communities fought the idea of water charges – and how only the mass revolt at the 2016 election managed to bring them to an end, even after Irish Water had fitted meters and issued bills for a couple of years.

The very fact that the national infrastructure was in such poor shape – with pipes from the 1800s buried so deep in capital cities, underneath more modern electricity and communications kit, that they’re impossible to dig up and fully replace – should already have suggested that Ireland’s water system was not a viable commercial project. But this was 2013 and 2014, with continued scrutiny over the links between Fine Gael and the businessman Denis O’Brien. The latter had a major share in one of the companies contracted to install meters nationwide – and, ironically, separately owned the company whose barriers were deployed on the streets of Dublin during the regular protests that followed.

Suddenly, there was a perception that O’Brien was in the market to buy Ireland’s water system – and a perceived inference that Fine Gael would be comfortable selling it to a former donor. The mere concept that a businessman could buy the system further lionised the protests, emboldening a movement that was already taking flight anyway – and prompted a subsequent push, even when charges were abolished, for a referendum to ensure water services would never be controlled by O’Brien nor anyone else.

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For the record: there is no concrete indication or suggestion that any investor ever wanted to buy the system. There didn’t have to be: some political parties made it an article of faith that the water system could never be sold, and continued occasional calls for a referendum to guarantee it.

When is a windfall not a windfall?

It’s not just on the opposition benches, or among the public, where ideas can take hold with zero evidence. Ministers are currently in the trenches of putting together the Budget, presenting wishlists to Merrion Street which will be rebuffed on the premise that much of the State’s current income cannot be relied on forever. 

It makes sense to be prudent on that front: so much of our tax revenue is concentrated in the profits of just three companies. The world’s in flux, and the White House wants American-headquartered companies to move their production (and revenues) home. 

But consider the three biggest taxpayers: Apple, Microsoft and Eli Lilly. The first has a massive complex in Cork and, although its intellectual property is mobile, still has a taxation advantage from keeping its operations headquartered here. The middle one also harnesses the same tax advantages to funnel revenue through here – the Irish operation records $7 million (€6.16 million) in profits per employee. The latter has huge manufacturing bases in Ireland, which it uses to create drugs like Mounjaro, one of the three globally dominant weight-loss drugs.

The prospect of those companies shutting up shop is, objectively, close to zero – so much so that the Department of Finance is still building these ‘windfall’ corporate taxes into its budget expectations, indefinitely. The ‘Annual Progress Update’ in April projected €20 billion in “windfall” taxes this year, and €21.3 billion next year, and more in 2028 and 2029… And even projected a further surge, to €26.7 billion, in 2030.

When is a windfall not a windfall? When you expect zero dropoff in how much it’ll yield, apparently forever more. But tell that to the ministers who are being told, this week, that there isn’t enough revenue available to fund the different spending commitments they’re hoping for.

What are the odds of that cash disappearing? Pretty much zero. But it doesn’t stop the perception becoming the foundation of how we run the country. 

Gavan Reilly is the Political Correspondent for Virgin Media News and the host of Monday with Gavan Reilly, which airs every Monday at 10pm on Virgin Media Play and Virgin Media One.