With Theresa May now Prime Minister, what might this mean for post-Brexit Britain? Some stability is returning to British politics, at least within the Conservative Party, after the resignation of the key proponents of the Leave campaign following the Brexit result.

Nigel Farage's resignation, soon after that of David Cameron and Boris Johnson's decision not to seek the Tory leadership, led to serious questioning of the tactics of the Brexit campaign, which Theresa May did not support.

The departure of the more strident Leave campaigners, who utilised a narrative of protection of sovereignty and of distinctiveness from the rest of Europe, did not allay concerns about the breakup of the UK and a recession in the offing. These are some of the problems facing Theresa May as she seeks to unite her party and the United Kingdom while attempting to negotiate with EU partners on the British exit.

Perhaps there is something to be learnt from the past – Brexit was not the first referendum in the UK on EU membership. The country held a referendum on its relationship with the EU on 5 June, 1975, just two years after it joined the then European Economic Community (EEC).

Therese May would know the current political debate bears remarkable similarity to the 1975 campaign. Sovereignty features prominently in both campaigns. And both included criticisms of the European Union as too powerful, too bureaucratic and undermining British sovereignty.

The 1975 National Referendum Campaign advanced the idea that the UK was distinctive and had little in common with the European continent. Both the Labour and Conservative parties were divided and politicians on both sides argued that continued membership would undermine Britain's economic and political interests.

Enoch Powell, a Right-wing Conservative MP, whom Nigel Farage openly admired, described the UK's membership at the time as 'a living death, the abandonment of all national rebirth'. On the Left, Tony Benn characterised continued membership as 'the end of Britain as a self-governing nation'. Yet, it is noteworthy there was little charismatic leadership on either side during the 1975 campaign.

Euroscepticism has remained a prominent feature of the UK's relationship with the EU, and has often framed the way the UK has approached European policy-making. As part of its reluctance to countenance an 'ever closer union', the UK succeeded in acquiring a series of opt-outs from EU policies and laws. Yet when it came to putting EU policies into practice, despite the critical stance taken by British politicians, the UK has been a dutiful partner in complying with EU laws.

It has always been a key advocate of the Single Market of four freedoms: of goods and services and capital movements – and people movement. It signed up to the mobility of workers as part of the Single Market package of 1992.

This adherence to economic principles, combined with a reluctance to take on board the more political features of the EU, has resulted in the UK earning a reputation as an 'awkward partner'.

Notwithstanding Winston Churchill's post-war support for the creation of a United States of Europe, he set the tone for British ambivalence with the contention that 'Britain is with Europe, not of Europe'. British accession in 1973 was not so much a commitment to the original principles of European integration, as a pragmatic calculation that joining the EEC was the best way to secure British economic interests in light of a trade deficit and the decline of the British Empire.

In June 1975, 67 per cent of British voters voted to remain in the European Community. In June 2016, however, 52 per cent of the British public voted to leave. What is different in 2016 is the rise – and success – of populism. The relentless focus on the threat of immigration was a clear message of UKIP's campaign in particular. This complemented the criticism of the EU as an elite project undermining British interests. Both were emotive – and controversial – tactics used by UKIP and some Conservatives.

Concerns about the unfolding refugee crisis was therefore a critical weapon used during the campaign by the Leave advocates. They argued EU membership meant an alarming increase in immigration from Eastern and Central European countries. Yet, this immigration formed part of the free movement of people, within the Single Market. This did not feature in the 1975 campaign.

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By focusing on the negative social and economic impact of the free movement of people, UKIP contended immigration had led to the abuse of welfare provisions and social services and that continued immigration would undercut the domestic labour force. The recent rise in post-referendum racist attacks against many communities, with a significant increase in hate crime, is indicative of this worrying anti-immigration trend.

It is not only migrants who were targeted in the Brexit campaign. There was also concern about the EU's difficulties in tackling the refugee situation across Europe. This provided another platform for the Leave campaign to condemn the EU. By framing the refugee crisis as a further threat to the UK's welfare system, UKIP was successful in appealing to a form of societal insecurity – and Theresa May herself spoke at the Conservative Party conference in 2015 of the need to cut benefits to migrants.

The irony of the populist argument is that the UK joined the EEC precisely because it provided greater economic and trade benefits. Membership has provided a market for British goods of over half a billion consumers across 27 countries. It boosted the economies of disadvantaged and poorer regions. Even Margaret Thatcher, a firm Eurosceptic, had been a keen advocate of the Single Market, including the free movement of people. By focusing on the threat of immigration and the consequences of the principle of free movement on the UK's labour force, Brexit campaigners were singularly successful in distracting voters from the economic risks of leaving.

The populist agenda has triumphed. The Brexit campaigners successfully appealed to the emotions of many British citizens. With the lack of strong leadership in the Remain camp, Farage and Johnson – now departed with mission accomplished – convinced voters of a better future outside the EU. What they and David Cameron have left as their legacy are leadership challenges in British politics.

It is clear in the aftermath of the Brexit result that EU membership remains as divisive as ever. The referendum's outcome led to the leadership battle within the Conservative Party, while the Labour Party faces increasing internal chaos and calls for leader Jeremy Corbyn to resign.

The political chaos has led to a serious questioning of the capacity of both major parties to secure a favourable deal for the UK. Some pro-EU Tory and Labour politicians are even calling for the formation of a new centrist political party to ensure those who voted to remain are not left out of the post-Brexit negotiations with the EU.

Theresa May will be under pressure to activate Article 50, although some legal experts are questioning whether it needs to be activated. Meanwhile, she will need to reassure other EU states who have been frustrated with British indecisiveness, a feature common to the UK-EU relationship.

A petition for a new referendum to reassess the legitimacy of the Brexit outcome has reached over
4 million signatures. Despite two referendums, do the British really know whether they're in or out? Will Theresa May be able to answer this question?

Banner Image: Theresa May makes a statement outside the House of Commons in London on July 11, 2016, after it became apparent she would replace David Cameron as Prime Minister. Picture: Carl Court/Getty Images