Would Zack Polanski’s wealth tax put artists at risk?

Zack Polanski has announced his intention to stand in the Holborn and St Pancras by-election. If elected, the Green leader would enter Parliament for the first time – and become London’s first Green MP. He has presented the by-election as a “referendum on ending rip-off Britain”.

His campaign will accordingly seek to place the taxation of wealth at the centre of the contest. Polanski will argue that voters should not accept becoming poorer while extreme wealth accumulates, and that tackling inequality through taxation should be a defining mission of government.

The argument will made with a telling backdrop. The constituency includes the British Museum, the British Library and Central Saint Martins, as well as a pocket of London’s commercial art trade, including TAFETA, Tristan Hoare, Alice Black and October Gallery.

In its 2024 general election manifesto, the Green Party proposed an annual wealth tax of 1% on wealth above £10m, rising to 2% above £1bn. Polanski reiterated the policy in a major speech in March this year, describing a wealth tax as a “day one priority” and saying it could raise around £15bn a year. An interview request with Polanski has gone unanswered at the time of writing.

Support for the policy extends to Hannah Spencer, the Green MP for Gorton and Denton and the party’s spokesperson for culture, media and sport. Speaking in Parliament in June, Spencer cited polling showing support for “a 2% wealth tax on net assets over £10 million”, before declaring that “properly taxing extreme wealth is part of our solution”. In a subsequent article on energy bills, she argued that a wealth tax could place costs more firmly on “those with the broadest shoulders”.

Spencer, who has not responded to a request for comment at the time of writing, has not explained how and if that principle should apply to privately owned art. Indeed, The Art Journal can find no substantive public comments from her on cultural policy since she assumed the brief. Her most notable cultural engagement appears to be hosting an evening of Palestinian film, literature, poetry and visual art at Levenshulme Old Library, Manchester, in July.

Capital gains or capital loss?

The party also proposes reforming capital gains tax by aligning the rates paid on taxable gains with income-tax rates. Its accompanying tax proposals are more explicit: realised gains would be taxed at the taxpayer’s marginal rate of income tax. Higher and additional-rate taxpayers currently pay a main capital gains tax (CGT) rate of 24%, meaning the Green proposal could substantially increase the rate applied to chargeable gains for wealthy sellers.

If the Green Party were to enter government – still a speculative prospect, but one that will become harder to dismiss if Polanski secured Keir Starmer’s former seat – what kind of impact would these policies have on the UK’s commercial art market?

The Green Party has not yet published the detailed tax base for its proposed wealth tax, including whether privately owned artworks would be included. Nor has it specified how frequently artworks might be valued for taxation purposes, whether culturally important works would qualify for exemptions or whether owners of illiquid assets could defer payment.

If art were included as taxable wealth, the combination of an annual levy on substantial assets and higher capital gains tax could fundamentally change how collectors buy, hold and sell artworks in Britain, and how dealers service them. It would ratchet up the pressure on a London market already buffeted by Brexit and unrelenting competition from Paris, Miami and New York, Hong Kong and the Gulf.

Compound bureaucratic issues would follow, with issues of valuation at its core. HMRC already has procedures for assessing art for existing taxes: its internal guidance on paintings and other works of art provides for specialist valuation of substantial works and collections. An annual wealth tax, however, could require repeated valuations of large privately owned collections whose market prices can fluctuate considerably.

Existing tax law also provides conditional exemptions for certain heritage assets, including objects of outstanding historic or artistic interest. A Green government would have to decide whether anything similar should apply to its wealth tax.

In response to a request for specific clarification, a spokesperson for the Green Party’s Executive Committee referred me back to their website.

My heart lies with grassroots art

There is perhaps an irony here, for Polanski has been unusually vocal among British politicians about the importance of supporting artists. In March 2024, while serving on the London Assembly, he successfully proposed a motion calling for greater cultural use of City Hall. “London’s theatre and art communities are in crisis across our city,” he said, “and deserve the full support of their Assembly Members and Mayor.”

More recently, speaking to NME in January this year, Polanski said his “heart lies particularly with grassroots art” and described it as “an amazing leveller; particularly in working-class communities”.

“People from marginalised communities making art is a fundamental way to tell your story,” he added. Elsewhere in the interview, he argued that art can contest political narratives: “Art is one of the most powerful ways you can do that.”

At the same time, Polanski presents the taxation of wealth as a challenge to political power as much as a means of raising revenue. On X, he has described the problem as “a system protecting the super-rich”. In another post, he called for a challenge to “the power & wealth of the 1%”.

Polanski has said the purpose is to reduce inequality: “If you allow people to hoard assets, that removes other assets for other people.”

For collectors, where does art collecting end and asset hoarding begin? 

Collecting or hoarding

London’s position as an art-market centre remains dependent on internationally mobile wealth, and the sector has long warned of capital flight. Collectors are attracted by a predictable commercial and tax framework, as well as the city’s ability to attract major consignments for sale and auction.

The latest Art Basel and UBS Global Art Market Report estimates that the UK accounted for 18% of global art sales in 2025. Transactions reached $10.5bn, up 2% year-on-year, keeping the UK in second place behind the United States and ahead of China, at 14%. France increased its share to 8%, with sales rising 9% to $4.5bn.

But this is not a secure footing. The report notes that the UK market continues to weather the challenges and complexities created by Brexit. Dealers surveyed in 2025 reported that rising tax and duty costs and greater administrative complexity were discouraging buyers, while Brexit was among the trade barriers specifically cited by dealers.

France, in particular, is sensing vulnerability. Art Basel Paris, housed in the majestic Grand Palais rather than a tent in Regent's Park, has arguably become a bigger draw for some top-tier collectors. London also competes for buyers with New York, Hong Kong and a growing art-market infrastructure in the Gulf. Frieze London remains an essential event for collectors, but its dominance of the contemporary art scene should no longer be taken for granted.

The taxman cometh

Art occupies a peculiar position for those with large fortunes. Unlike shares, rental property or businesses, most artworks produce no income. They may appreciate in value, but they also generate insurance, conservation, storage and security costs. Their other returns – prestige, access, cachet – are real but intangible, and cannot easily be entered on a tax form.

Art is not entirely outside the current tax system. HMRC generally treats paintings and other works of art as non-wasting chattels for CGT purposes. A single personal possession sold for £6,000 or less is generally exempt, with special marginal relief applying above that level. But high-value artworks can generate chargeable gains when sold. The Green proposal would therefore change the rate at which taxable gains are charged rather than introduce CGT to valuable paintings for the first time.

But a wealth tax would really up the stakes. If artworks were included, liability could arise simply from continuing to own them. A painting might be worth millions on paper without producing a penny of income. Unless the eventual scheme included some form of deferral for asset-rich but cash-poor taxpayers, its owner would nevertheless need sufficient liquid assets to meet an annual HMRC bill.

For collectors whose wealth exceeded the threshold but was tied up substantially in art without correspondingly large cash reserves, the tax could encourage them to sell works, borrow against them or buy fewer works in future. Greater reliance on art-backed lending – and the steep costs of being unable to repay a debt – could in turn leave collectors more exposed to interest rate changes and sudden shifts in market conditions.

More important for artists would be what happens before this point. If collectors anticipate an annual cost attached to owning art, some may simply reduce their acquisitions. For the very richest buyers, a 1% charge may make little difference. For others, particularly those close to the threshold or with substantial illiquid collections, it could make the difference between a significant outlay and a fallow fair or the paddle staying down at auction.

If the tax results in fewer acquisitions, the consequences could travel quickly down the chain: less revenue for galleries can mean fewer exhibitions, smaller production budgets and reduced advances to artists. That possibility sits awkwardly beside Polanski’s pledge to support London’s “art communities are in crisis”.

The cost of tax

The tax could also make disagreements about an artwork’s value significantly more consequential. Gallerists, advisers and collectors routinely disagree about questions of market price and have long conversations about attribution and condition. But these are not, currently, major concerns for the tax man.

But, under a wealth tax that included artworks, those disagreements would no longer just matter when something was bought, insured or sold. They would determine the amount of tax the collector owed every year. They may make the difference between a hand-shake and a quick exit.

The Green Party’s proposals would not stop wealthy people from buying art. But they would dramatically impact on how much art they keep in Britain, how frequently they sell, where transactions take place and, at the extreme, where they establish their tax residence. London gallerists have worked hard to secure the trust of top collectors. For this group, buying in New York, Hong Kong, Dubai or Paris rather than London is little more than a first-class flight and a nice hotel away. Disrupting those bonds would be felt across the food chain. 

If Polanski reaches Parliament, this tension will become more than theoretical. Include art in the wealth-tax base and the Greens risk weakening a private market on which many artists and galleries depend. Exempt it, and they could create a refuge for the very wealth Polanski accuses the rich of hoarding. The party has yet to explain whether any of the projected £15bn in receipts would reach artists, or whether public support would replace private spending lost along the way. 

Until it does, Polanski’s two ambitions – confronting accumulated wealth and rescuing a cultural sector in crisis – remain in conflict. In ending rip-off Britain, the Greens still have to convince that artists won’t get ripped off.