The Polarization Tax: How Britain's Internal Divides Shape Foreign Policy Outcomes

A Colossus with Feet of Clay

With a 1.6-point increase in vote share, the Labour party more than doubled its electoral results in the 2024 general election, obtaining a landslide victory with a majority of 411 MPs. The Labour electoral success is undeniable; however, these very results actually suggest that this triumph is a colossus with feet of clay: the election itself was dubbed as “the most disproportionate” with approximately one third of the votes winning two thirds of the Parliament seats. The case with Liberal Democrats is even starker: an increase in 0.6 percentage points (pp) produced an outstanding boost from 8 to 72 seats. These surprising victories can actually be well-explained by one phenomenon: political polarization.

Political polarization is the divergence of political attitudes from the center towards ideological extremes. It can pertain to policy preferences or be affective, implying that the supporter of one camp actively dislikes the supporter of another camp on a personal level; it can be mass or elite. In some “severe” cases it may take the form of everything that is mentioned above and currently that is what is being witnessed in such countries as the United States or the United Kingdom. While the U.S. case went for a widening gap between two main parties (unlike in the 1890s), the UK case is characterized by the increased fragmentation.

Source: Freepik

How Did It Come to This?

The watershed moment of British political polarization was the referendum on Brexit, which produced an almost fifty-fifty split, in a stark contrast to the referendum on essentially the same issue of 1975, when approximately two thirds of Britons voted to remain. This fifty-fifty vote had already been a sign of political polarization, but it pertained mostly to the masses, not the elites. However, with the resignation of David Cameron and attempts to redefine the Conservative party’s identity, political polarization began to affect the elites, especially the two long-standing parties.

These polarization tendencies produced the ensuing Conservative leadership crises: firstly, of Theresa May, then, in time, of Boris Johnson and Liz Truss. During the “meaningful vote” Theresa May actually suffered the largest government defeat in UK history by 230 MPs, including deserting 118 conservative MPs. Labour also suffered a rebellion at that time: the “Change UK” breakaway was formally the largest since 1981. After the 2024 election Labour also suffered whip rebellions and enacted suspension both in 2024 and 2025. Alongside internal crises, both Conservative and Labour parties suffer external rating setbacks, most notably from Nigel Farage’s Reform UK, but increasingly from the Green Party in addition to the more traditional Liberal Democrats.

The interim result of these tendencies can be seen at the 2026 May local elections. Essentially, the political landscape is now fragmented among five parties—from Reform UK to the Green Party of England and Wales—that command relatively comparable shares of the vote. For example, the difference between Liberal Democrats (844) and Conservatives (801) is only 43 seats in favor of the former, an unimaginable result for a formally two dominant parties system. In other words, bipartisan politics is gone, at least for a while. Moreover, even though Reform UK leads the votes, its advantage is also not overwhelming: for example, in Wales, which Nigel Farage once called a “priority,” the voters consolidated behind Plaid Cymru, a nationalist party, and defeated Reform UK 43 to 34 seats respectively.

The Polarization Tax and Foreign Policy Implications

While traditionally foreign policy relies on a degree of domestic consensus, which, as a famous saying goes, “stops at the water’s edge,” political polarization erases the limits. Fragmented party politics and political polarization make traditional parties more cautious lest they lose voters, which, ironically, often only fosters the loss of voters as people become disillusioned with flaccid responses to the problems. For example, although Sir Keir Starmer wanted to soften his rhetoric on Brexit, he accepted the advice from his polling advisers that it “would cost Labour many of the votes it needed to return to government.” Likewise, led by the same motivation, the Labour government produced a very limited UK-EU 2025 reset—far more confined than it would have been if no such electoral threats were present. But these very threats were a result of widened political polarization.

However, political polarization also entails the following challenges beyond cautious negotiations and accelerated race for voters’ preferences: firstly, it erodes stable foreign policy across time. If before the Tories and Labour had bipartisan consultations, which helped settle differences and produce a coherent foreign policy framework, now it will have to be four-, five- or even six-party consultations, which narrows a room for agreement. Indeed, Brexit and rapprochement with the European Union still remains a sensitive issue, effectively producing “for” and “against” camps. The Labour Party, which wants to straddle, finds it increasingly difficult to do it over time.

Secondly, it undermines the credibility of threats to adversaries. When there is a lack of consensus in foreign policy, other countries might be willing to wait for another, more compliant party to come to power. For example, on January 7, 2026, Sir Keir Starmer signed a "declaration of intent” with Emmanuel Macron to deploy troops in Ukraine once the peace deal is achieved. On the same day Nigel Farage openly rejected the idea, weakening its credibility.

Thirdly, it decreases the reliability of commitments to the allies as another party might have a very different plan for future relations. For instance, the Labour government has canceled an already negotiated Rwanda deportation plan. Or Nigel Farage said that “We'd tell the EU that any agreements are no longer legally binding on the UK, because a general election has said so,” which undermines the credibility of any UK-EU deals as Reform UK continues to lead in polls. The same logic can be applied to the 2019 Theresa May’s deal, when an already negotiated one suddenly failed to make it through. All of these cases make any negotiations with Britain structurally conditioned and haphazard.

Thus, together it all functions as a structural Polarization Tax: with favorable capabilities (and 411 MPs are nothing less than a very advantageous position) Britain is able to negotiate less favorable deals, it squanders its diplomatic capital, and it makes an overall foreign policy less coherent, dynamic, proactive and efficient. In other words, Britain (and indeed every other country) “pays” the polarization tax, making its foreign policy clumsier and more dysfunctional.

Furthermore, the conditionality and scope of the tax depend on the issue at hand, how both elites and public relate to it, what the commitment is about and how visible other alternatives are. In turn, different domains might be “taxed” with different currencies: negotiations might require additional time and offer worse conditions, trust between allies might erode and the apprehension of the adversaries may lower. Though it shall be acknowledged that in some cases the tax could deliver the benefits: the country’s representatives might bury some unfavorable propositions referring to the complicated domestic situation even if that is not particularly accurate.

The Long Road Ahead

That is not all to say that there are no overlapping themes in the UK altogether: for instance, all major parties agree that the United States is a key partner of the United Kingdom with which it enjoys the special relationship as well as that China is a security threat to Great Britain. But it shall be nevertheless stated that the number of such themes has decreased in recent years: from the environmental policies to the UK participation in the Ukrainian conflict.

What is currently observed is, probably, a prolonged electoral shift of the same sort that is happening in the United States. Although in the short or medium run, this state of fragmentation will remain evident, in the long run it is likely to decrease. Indeed, it is not the first time for Britain to experience political polarization: the Chartist Movement, Edwardian crisis of 1909-1914 or Thatcher era are all relevant cases, when political polarization rapidly rose and then inevitably declined.

In practical terms, powers negotiating with the United Kingdom shall envision shorter commitment horizons as well as try to institutionalize every arrangement through treaties rather than informal executive-level agreements. It shall also engage opposition parties and other relevant stakeholders: the example here is the Windsor Agreement over the status of Northern Ireland after the UK left the EU, where the European officials have engaged Northern Irish stakeholders. The treaties shall also feature an escape clause, which can additionally give some flexibility in negotiations with a hypothetical new government.

If to look at the broader picture, it can be stated that the UK case is not unique and, moreover, that the polarization tax it is experiencing is seen in other countries: post-2024 France (and most likely post-2027 as well), Germany with AfD pressure, Spain and so on all highlight relevant examples. Thus, although currently the United Kingdom is one of the most emblematic cases, the consequences of the “taxation” will be witnessed throughout the region and indeed the world with respect to middle powers’ foreign policy in times of political polarization.

Nevertheless, if Britain is about to fulfill its “Global Britain” ambition and not to be relegated with a title of an unpredictable middle power instead of a reliable global leader, then the reverse of political polarization must happen sooner than later. Though as for now, the costs of the polarization tax will continue to compound.