Zack Polanski’s Wealth Tax Gamble: How the Green Party’s New Economics Are Rewiring UK Politics

Three months ago, Zack Polanski was a relatively obscure Green politician. Today he is at the centre of Britain’s fiercest argument about tax, debt and the future of the left – hailed by some as the hopeful face of a new politics, condemned by others as an “economically illiterate populist” with “insane” ideas about money.

This piece pulls together the latest reporting, polling and economic analysis around Polanski’s platform as of early December 2025, and explores what his rise could mean for the UK’s political and economic trajectory.

From fringe figure to polling phenomenon

Zack Polanski was elected leader of the Green Party of England and Wales in early September 2025, taking over after the party’s record four seats in the 2024 general election pushed the Greens closer to the Westminster mainstream. ^[1]

Since then, the numbers have moved fast:

Polling surge: A YouGov poll conducted on 16–17 November and reported by The London Economic put the Greens on 17%, level with the Conservatives and just two points behind Labour on 19%, with Reform UK out in front on 27%. ^[2]
Youth support: The same coverage noted that recent polling for ITV showed the Greens with a “commanding lead” among 18–25-year-olds, and strong support among under‑50s more widely. ^[3]
Membership boom: A detailed profile in The Badger reports that Green membership has surpassed the Conservatives, topping 125,000 members and roughly doubling since Polanski became leader. ^[4]
Media visibility: Guardian columnist Gaby Hinsliff argues that Polanski’s “burgeoning popularity” has turned him into one of the “most underpriced wildcards” in British politics, with broadcasters giving him almost as much airtime as Conservative leader Kemi Badenoch and far more than the Liberal Democrats’ Ed Davey in early autumn. ^[5]

On Today in Focus, the Guardian’s flagship podcast, reporter Nosheen Iqbal followed Polanski to an event at King’s College London and found him playing to packed student audiences. The show notes describe a party whose membership has more than doubled in three months and a leader whose “positive and hopeful” tone, built around “people power” rather than “multimillionaires and billionaires”, is clearly landing with younger voters. ^[6]

In other words, whether you like his economics or not, Polanski is no longer a fringe player.

Inside Polanski’s economic agenda

Wealth tax and “tax wealth, not work”

Polanski has made radical tax reform the centrepiece of his economic pitch.

According to The Badger’s overview of his programme, he is pushing for: ^[7]

A wealth tax on the “super rich”, framed as a way to “tax wealth, not work”;
Using that revenue to fund universal free childcare, expanded SEND (special educational needs and disabilities) provision, and better NHS and welfare services;
Broader structural change, including proportional representation and higher overseas aid (up to 1% of GDP).

On social media, Polanski has been even more direct. In a late‑November post on Bluesky, he declared that “the country wants a wealth tax on assets”, claiming that the old warning that “the rich will just leave” has been “utterly debunked”, and urging supporters to join the Greens. ^[8]

That stance aligns him with a widening cluster of voices across the left arguing that taxing assets, rather than just incomes, is now essential to tackle inequality. A recent opinion piece in North East Bylines notes that former Labour leader Neil Kinnock has also called for a wealth tax, and quotes Sky News’s description of such levies as direct taxes on net assets – everything from property and shares to savings – after debts are deducted. ^[9]

Modern Monetary Theory in the background

Critics and supporters alike see echoes of Modern Monetary Theory (MMT) in Polanski’s interviews.

In a widely discussed column for The Spectator, Christopher Snowdon points to Polanski’s appearances on the BBC’s Sunday with Laura Kuenssberg. There, Polanski argued that the state can fund “public investment” without needing a wealth tax and described loans from the Bank of England as “money we owe to ourselves”, insisting that a household budget is “nothing like a national budget”. ^[10]

For Snowdon, those are classic MMT talking points: the idea that a government issuing its own currency need not rely on taxes or conventional borrowing to spend, so long as it keeps inflation under control. ^[11] He concludes that Polanski has “fallen down the rabbit hole of MMT” and calls the policies derived from that worldview “insane”. ^[12]

Modern Monetary Theory itself is controversial but not fringe in academic debate. Mainstream explanations stress that while currency‑issuing governments have more room for manoeuvre than households, they still face real constraints via inflation, exchange rates and bond markets. ^[13] The argument between Polanski and his critics is essentially about where those constraints really bite – and how much risk is acceptable.

The Telegraph: “economically illiterate populist – just like Farage”

If The Spectator focuses on theory, The Telegraph goes for competence.

In a paywalled column syndicated on Yahoo and trailed by its author James Baxter‑Derrington on LinkedIn, Polanski is branded “an economically‑illiterate populist – just like Farage”. The piece accuses him of not knowing: ^[14]

the top rate of income tax;
the scale and ownership of the national debt;
what the Bank of England actually does;
what counts as a “sovereign currency” or even, in the author’s phrasing, “what an economist is”.

Baxter‑Derrington argues that, while Polanski complains about personal attacks, his policy demands amount to a wholesale restructuring of the domestic and international economy without a basic grasp of the existing system. He likens Polanski’s style to Nigel Farage’s, accusing him of lifting from “the populist playbook” by offering “easy answers to difficult problems”. ^[15]

For Telegraph readers, the message is straightforward: this is not just a radical programme, but one advanced by a leader who, in the columnist’s view, does not understand the basics.

The Spectator: MMT “snake oil” and bond‑market fears

Snowdon’s Spectator column goes deeper into the macroeconomics. ^[16]

His core claims are:

Polanski’s insistence that Britain can invest without new taxes implies that taxes do not fund spending, a core MMT contention;
His description of central‑bank‑held debt as “money we owe to ourselves” is technically accurate but, Snowdon argues, misleading if it encourages politicians to ignore overall debt levels;
Talking as if bond markets can be brushed aside risks repeating – or exceeding – the turmoil seen after the 2022 “mini‑budget”, when markets rebelled against unfunded tax cuts.

Snowdon accepts that some MMT‑style observations (for example, that a government’s finances are not identical to a household budget) are technically true. But he insists this school of thought is “simply nonsense” as a guide to policy, warning that its implications for borrowing and taxation are “insane”. ^[17]

Although polemical, this critique taps into a wider concern: after a decade of crises, investors, ratings agencies and institutions like the OECD are intensely focused on fiscal credibility. The OECD’s latest outlook for the UK, for example, warns that higher taxes and spending restraint in Rachel Reeves’s budget will dampen consumer demand, even as it slightly upgrades the UK’s growth forecast for 2026. ^[18]

For Polanski’s critics, doubling down on borrowing and wealth taxes at the same time looks like tempting fate.

Supporters see something very different

Where right‑leaning commentators see recklessness, Polanski’s fans see clarity and courage.

On the Guardian’s Today in Focus podcast, young voters at King’s College London describe him as unusually direct and “hopeful”, contrasting his tone with what they see as Labour’s caution. Polanski himself frames his message as “positive” and rooted in “people power” rather than deference to billionaires. ^[19]

Gaby Hinsliff’s Guardian column goes further, suggesting that if current trends continue, the Greens could overtake Labour in the polls, much as Reform UK has overtaken the Conservatives on the right. That crossover point, she argues, would be “seismic”, reshaping perceptions of what counts as a “wasted vote” on the left. ^[20]

Elsewhere, The Badger highlights how Polanski has turned the Greens into a serious vehicle for disillusioned progressives: matching the Conservatives in national polls, topping the membership tables, and becoming the most popular party among 18–24‑year‑olds. ^[21]

Against the backdrop of Your Party’s very public implosion – riven by factional warfare between supporters of Jeremy Corbyn and Zarah Sultana – some analysts argue that the space for a left‑of‑Labour challenge has effectively defaulted to the Greens. ^[22]

In that framing, Polanski is less a dangerous outlier and more the figure finally articulating demands many younger and left‑leaning voters already hold: tougher action on climate, a more aggressive approach to inequality, and a willingness to question economic taboos around debt and taxation.

Do the numbers add up? What economists say about wealth taxes and MMT

Wealth taxes: high hopes, modest realities

In the UK debate, wealth taxes are often presented – by both supporters and opponents – as a radical break with the past. Globally, the story is more mixed.

An OECD study on the design of net wealth taxes finds that only a handful of countries now use broad, recurring wealth taxes, and that revenues have generally been modest as a share of GDP despite rising wealth. ^[23]
Recent reporting on Europe shows that in 2023 Switzerland raised about 4.3% of overall tax revenue from wealth taxes, while Spain raised about 0.6%, Norway 1.5% and France only 0.2%. ^[24]
The UK’s Institute for Fiscal Studies (IFS) argues that an annual wealth tax could raise significant sums, but would be “difficult” to administer and would need to cover a very wide range of assets to avoid easy avoidance. They suggest that reforming existing taxes on wealth (capital gains, inheritance tax, property taxes) may be a more practical route. ^[25]

The global politics of the issue are equally nuanced. In Switzerland, voters last week overwhelmingly rejected a proposal for a 50% inheritance tax on fortunes above 50m Swiss francs, with 79% voting against. ^[26] Business groups warned it would scare off the wealthy; supporters argued that extreme wealth should finance climate action.

Polanski’s claim that “the rich won’t just leave” if the UK introduces a wealth tax is not plucked from thin air. Studies reviewed by the Tax Justice Network in 2025, and work by sociologist Cristobal Young, find that millionaire migration in response to higher taxes is typically very low, with most wealthy individuals having strong social and business ties that keep them anchored. ^[27]

A Guardian “Friday briefing” earlier this year similarly concluded that headlines about a mass exodus of the ultra‑rich from Britain are not backed up by the data, although high‑profile departures can still shape the narrative. ^[28]

The economic jury, in other words, is mixed: wealth taxes can raise money and may not trigger a stampede of millionaires, but they are complex, politically contested and no silver bullet.

Modern Monetary Theory: more room, not no limits

On MMT, the academic picture is also more subtle than the polemics suggest.

Modern Monetary Theory starts from a simple observation: countries that issue their own currency cannot involuntarily “run out of money” in the same way households or eurozone governments can. They can always create more money to pay domestic obligations; the true constraints are inflation, real resources and political legitimacy. ^[29]

Even economists sympathetic to some MMT insights stress that:

Taxes still matter enormously – for managing inflation, shaping behaviour and legitimising the currency; ^[30]
Bond markets and exchange rates are real constraints, especially for open economies like the UK that rely on foreign investors;
Political discipline is essential: the fact that a government can create money does not mean it should, particularly in a high‑inflation world.

From that perspective, the argument around Polanski is not about whether the state can expand spending without matching tax rises immediately – it clearly can – but about how far and how fast it should push that lever, and what balance between borrowing, taxation and money creation is prudent.

A fragmented party system – and Labour’s new headache

Polanski’s rise is unfolding in a chaotically crowded party system:

On the right, Reform UK and Nigel Farage are now polling well ahead of the Conservatives; some analyses put Reform close to 30%, with the Tories languishing in the high teens. ^[31]
On the left, the attempt to create a Corbyn‑aligned “Your Party” has been badly damaged by public infighting, resignations and legal threats, according to detailed Guardian reporting. ^[32]
In the centre, Labour is juggling governing pressures, a cooling economy and internal arguments over the scale of fiscal tightening set out in Rachel Reeves’s budget – criticisms that the OECD’s latest forecast both softens and partially echoes. ^[33]

That leaves Labour exposed from two directions:

To the right, from Reform, on issues like migration and crime;
To the left, from Polanski’s Greens, on climate, inequality and Palestine – with polls and membership figures suggesting the Green threat is becoming more real rather than less. ^[34]

Hinsliff notes that if the Greens do overtake Labour in the polls – even briefly – the psychological impact could be huge. Suddenly, a vote for the Greens would no longer look “wasted” to disillusioned Labour supporters; it would look like backing the new frontrunner on the left, just as Reform has become the default protest vehicle on the right. ^[35]

Three possible futures for the “Polanski moment”

It’s too early to know whether this is just a spike of enthusiasm or the start of a long‑term realignment. But current data and expert commentary point to three broad scenarios.

1. Agenda‑setter without power

In this scenario, the Greens settle into the high teens in national polling but fall back somewhat as a general election nears, squeezed by fears of letting Reform or the Tories in.

Labour retains a commanding presence in parliament;
The Greens secure a modest increase in MPs, enough to get more broadcast time but not to dictate policy;
Polanski’s wealth‑tax and MMT‑adjacent ideas nevertheless shape the wider debate – pushing Labour towards tougher action on inequality and green investment, even if the actual policy adopted is more cautious. ^[36]

This is roughly what happened in earlier periods with UKIP and, later, the Brexit Party: they changed the agenda long before they changed the composition of government.

2. Coalition influencer

A more dramatic path would see the Greens sustain or increase their poll ratings, making them a pivotal partner in a future hung parliament or centre‑left coalition.

Under that scenario:

Polanski’s fiscal ideas might be partially implemented – for example, a limited wealth tax on ultra‑high net worth individuals combined with reforms to capital gains and inheritance taxes; ^[37]
The party could win significant new spending on climate and public services, constrained by coalition agreements and market pressures;
MMT‑style language about “money we owe to ourselves” might become more normalised in political discourse, even if the Treasury quietly operates within more orthodox limits. ^[38]

Whether markets would tolerate this depends on broader conditions: growth, interest rates and confidence in Britain’s institutions. The OECD currently sees the UK’s growth modestly outpacing France and Germany in 2026, but warns of headwinds from global slowdowns and high tax burdens. ^[39]

3. The bubble bursts – but leaves a legacy

Finally, it’s possible that Polanski’s surge is relatively short‑lived:

A scandal, a poor campaign, or a serious economic shock could sap support;
Labour might respond with targeted policy shifts – for example, modest tax measures on wealth and stronger climate commitments – that win back disaffected voters;
The Greens slide back into single digits by the time of the next general election.

Even then, the episode would likely leave traces. The combination of polling spikes, viral clips and intense commentary from outlets ranging from The Spectator to The Telegraph and The Guardian has already forced mainstream politics to confront questions about wealth, debt and the limits of fiscal policy more openly than at any point since the post‑crash years. ^[40]

What the debate around Polanski really tells us

Strip away the headlines about “insane economics” and “economic illiteracy” and the fight over Zack Polanski is really a fight over three big questions:

How much inequality is Britain prepared to accept?
Wealth has grown rapidly at the top, while wages and public services for many have stagnated. Wealth taxes, higher capital gains taxes and tougher rules on non‑doms are all different ways of answering that question. ^[41]
How scared should we be of public debt?
MMT‑influenced arguments downplay crude debt‑to‑GDP ratios and emphasise real‑world constraints like inflation and capacity. Traditional fiscal conservatives, including many at the OECD and IFS, worry that treating debt as “money we owe ourselves” risks repeating the errors that triggered recent market turmoil. ^[42]
Who gets to define “responsible” economics?
Newspaper columnists, rating agencies and think‑tanks have long policed the boundaries of acceptable policy. The Polanski debate shows a new generation of voters and activists far less willing to take those boundaries for granted, especially after years of austerity, Covid spending and inflation. ^[43]

For now, Polanski embodies that tension: a leader whose critics see him as dangerously naïve about economics, and whose supporters see him as finally telling the truth about how money and power really work.

What happens next will depend less on the finer points of MMT and more on whether the economic mood of the country – against a backdrop of slow growth, high rents and climate anxiety – continues to favour those prepared to tear up old rulebooks.