The referendum in Britain regarding leaving the European Union (EU) was commonly known as the "Brexit" referendum. It took place on June 23, 2016. The referendum asked voters the question, "Should the United Kingdom remain a member of the European Union or leave the European Union?"

David Cameron, the Prime Minister of the United Kingdom from 2010 to 2016, called for a vote on Brexit due to a combination of political and strategic reasons. Within his own party, the Conservative Party, there were long-standing divisions on the issue of European Union (EU) membership. To manage these divisions and unite the party, Cameron promised a referendum on EU membership in his 2015 election manifesto. Additionally, there was growing public pressure for a referendum, fueled by the rise of euroscepticism and calls from voices like the UK Independence Party (UKIP). By calling for a referendum, Cameron aimed to address this public pressure and provide a democratic mandate on the UK's EU membership. He also sought to renegotiate the terms of UK membership with the EU, particularly focusing on concerns related to immigration and sovereignty. By calling for a referendum, he aimed to strengthen his negotiating position with the EU. Personally, Cameron campaigned for the UK to remain in the EU and expected that the referendum would result in a vote to remain. He believed that the economic arguments, expert opinions, and party/public support would sway voters to choose to remain.

Arguments in favor of leaving the EU, often referred to as the "Leave" campaign, included:

Sovereignty: Leave campaigners argued that leaving the EU would restore the UK's sovereignty, allowing the country to have full control over its laws, borders, and trade policies without being subject to EU regulations.

Immigration control: Leave supporters expressed concerns about the free movement of people within the EU, arguing that leaving would enable the UK to regain control over its immigration policy and reduce the number of EU migrants coming to the country.

Economic independence: Some proponents of leaving argued that the UK could forge new trade agreements with countries outside the EU, allowing for greater economic flexibility and independence.

Financial contributions: Leave campaigners highlighted the financial contributions the UK made to the EU budget, suggesting that leaving would free up funds to be spent on domestic priorities like healthcare and education.

Arguments in favor of remaining in the EU, known as the "Remain" campaign, included:

Economic stability: Remain supporters emphasized the benefits of EU membership for trade, investment, and access to the EU single market. They argued that leaving the EU would create economic uncertainty and potentially harm the UK's economy.

Security and influence: Some proponents of remaining argued that EU membership provided the UK with greater security cooperation, particularly in areas such as counter-terrorism and intelligence sharing. They also believed that being part of the EU strengthened the UK's global influence.

Worker and consumer rights: Remain campaigners stressed that EU membership protected worker rights, consumer standards, and environmental regulations, arguing that leaving could result in a loss of these protections.

Collaboration and peace: Some supporters of remaining highlighted the EU's historical role in fostering peace and stability in Europe, suggesting that leaving could disrupt this cooperation and potentially strain relationships with other EU member states.

Regarding political parties, the Conservative Party was divided on the issue, with then-Prime Minister David Cameron and a majority of Conservative MPs supporting the "Remain" campaign. However, some prominent Conservative figures, including Boris Johnson, Michael Gove, and others, campaigned for the UK to leave the EU.

The Labour Party, led by Jeremy Corbyn at the time, officially supported remaining in the EU, although there were divisions within the party, and some Labour MPs and supporters advocated for leaving.

The UK Independence Party (UKIP), led by Nigel Farage, strongly campaigned for leaving the EU. Other smaller parties, such as the Democratic Unionist Party (DUP) and the Green Party, also took positions in favor of remaining in the EU.

Brexit was a significant issue because it involved fundamental questions about the UK's relationship with the EU, its sovereignty, economic future, and identity. The debate and subsequent referendum result had profound implications for the UK's political landscape, its economy, and its international relations.