The Conservative party historically is among the most successful political parties in Western Europe with an unrivalled capacity to win and retain governmental office. In the 20th century, the Conservatives dominated British politics for most of the 1920s, 1930s, 1950s, 1980s, and 1990s.

Thirteen out of sixteen Conservative leaders during that period went on to become Prime Minister. The Tory party had mastered what the political scientist Jim Bulpitt described as the art of ‘statecraft’, the task of achieving and sustaining governing competence within the British polity to successfully marginalise alternative political forces, chiefly the threat of socialism posed by the Labour party.

Since the Conservatives’ ejection from office in the late 1990s, however, the party appears to have renounced its winnings ways. Not since 1987 have the Tories won a convincing parliamentary majority. After 1997, the Conservatives lost three consecutive elections for the first time in modern British political history. Their electoral marginalisation was a reflection of growing internal divisions within the Tory party, the primary cause of which was how to handle the European question in British politics.

The Conservatives had traditionally favoured British membership of the European Community as a means of arresting Britain’s post-imperial decline, successfully negotiating entry under Edward Heath in the early 1970s. But the dynamic of European integration posed new dilemmas for leading Tory politicians in the 1980s and 1990s.

Conservative Prime Ministers such as Margaret Thatcher wanted to influence the future direction of Europe by championing projects such as the European single market after 1985 which they believed would help to make the UK economy more competitive and dynamic.

At the same time, Tory politicians were increasingly repulsed by the vision of Europe foreseen by other leading member-states, particularly France and Germany, eventually enshrined in the 1992 Maastricht treaty. Their opposition reached its zenith in Thatcher’s growing hostility to monetary integration and the goal of a single European currency in the late 1980s, alongside the burgeoning regulations and red tape apparently associated with single market membership.

On the other hand, pro-European Conservatives such as Geoffrey Howe, Kenneth Clarke and Michael Heseltine were demanding Thatcher’s ejection from Number Ten by 1990. They believed Thatcherism’s growing antipathy and visceral dislike of Europe were threatening the Conservative party’s claims to governing competence. The consequence of Thatcher’s defenestration has been several decades of bitter Tory infighting over Europe.

Europe has been so problematic for the Tory party not merely as an external policy issue in its own right, but because British membership of the EU highlights the contested nature of modern Conservative politics and ideology. The EU strikes at the heart of major unresolved questions of ideology, identity and political economy, as well as the question of how the Tories should define their vision for Britain.

This situation is complicated by the deep attachment to sovereignty in Westminster politics, particularly on the right. And as Andrew Gamble has shown, the Conservative party is profoundly divided because many on the centre-right of British politics reject Britain’s engagement in European political integration, embracing an ‘Anglo-American’ world-view which perceives Britain’s strategic and militarily alliances, its model of capitalism, its system of governance, and its prevailing doctrines and political ideas to be predominantly influenced by the United States rather than Europe. This contestation over institutions and ideas is the root cause of Tory antipathy to the European Union.

Such political divisions that have prevailed for three decades have returned to haunt Theresa May’s premiership. The decision of British voters to ‘leave’ the European Union in the 2016 referendum was supposed to end the UK’s uncertainty and ambivalence about Europe, but the vote appears to have exacerbated the turmoil and confusion over European policy and Britain’s world role.

This sense of mounting chaos has been accentuated by the failure of the Conservatives to win a parliamentary majority in the 2017 general election, severely depleting May’s political authority.

Although there is growing acceptance in the Cabinet of the need for ‘transitional arrangements’ over single market membership and freedom of movement as championed by the Chancellor, Philip Hammond.

The party is in reality divided between those who favour a ‘soft Brexit’ centred on maximising ongoing engagement with the EU, and those such as Liam Fox, David Davis and Michael Gove who are committed to a swift departure, if necessary without an EU trade deal in place. They believe that they have won a generational battle to regain national sovereignty and political control for the citizens of the United Kingdom, and are unlikely to give up easily.

As such, the referendum outcome has palpably failed to end the disagreements within the Conservative party over how to handle the European issue. Those figures such as the former Education Secretary, Nicky Morgan, who favour a ‘soft’ Brexit are concerned about the electoral and political implications of a poorly handled Brexit process. They argue that an ill-conceived Brexit deal would imperil the Conservatives’ reputation for economic competence, while undermining the territorial integrity of the UK by encouraging Wales and Scotland to consider a European future outside Great Britain.

The so-called ‘Soft Brexiteers’ recognise that the City of London, the financial markets, and much of corporate Britain are unnerved by the prospect of moving overnight to a unilateral trade policy that would inflict a major structural shock on the British economy. These politicians are unlikely to accept a ‘hard’ Brexit arrangement which they fear will destroy the long-term electoral and political prospects of the Conservative party in British politics, while increasing the likelihood of Jeremy Corbyn entering 10 Downing Street.

The 2016 referendum was intended to settle once and for all the question of Britain’s future relationship with the European Union. The unintended outcome, however, has been to further divide the Tories, thereby posing a fundamental question about the long-term viability of the Conservative party as a serious contender for power in UK politics.

By Dr Patrick Diamond, lecturer at Queen Mary’s University London