With Article 50 triggered and Brexit negotiations well underway, the UK government looks like it’s carrying out the instructions it received from 17.4 million voters last summer. At best, Britain and the continent will establish a mutually advantageous trade relationship; at worst, the UK and EU will revert to World Trade Organization (WTO) rules, including minor tariffs on the exchange of goods and services. In either case, it seems, the UK will regain control over its finances, its borders, and its laws –all of which are necessary to fulfill the mandate given by voters.

Nevertheless, a growing threat hangs over Brexit Britain.

In hopes of consolidating power, Prime Minister Theresa May called an election in June. Rather than expand her mandate with a comfortable majority in Parliament, May’s Conservatives lost their majority, necessitating the support of Northern Ireland’s Democratic Unionist MPs to govern.

Emboldened by the election result, opposition parties have redoubled efforts to undermine the government’s position in Brexit negotiations. By seeking guarantees that single market access is maintained at all costs, or that, if by March 2019 (the date by which the UK has notified the EU it will leave) negotiations have not born fruit Britain’s current relationship with the EU should be maintained, MPs from Labour, the Liberal Democrats, the SNP and even some Conservatives are undermining the primary objective of last year’s referendum: to leave the EU.

Beyond Westminster, a growing number of voices have added themselves to the anti-Brexit bandwagon.

Devolved administrations in Scotland and Wales have expressed concern over the UK government’s “great repeal bill”, meant to repeal the European Communities Act of 1972, and bring all EU law currently applying to the UK into British statute. Scottish and Welsh first ministers Nicola Sturgeon and Carwyn Jones see the bill as a “power grab” by Westminster, supposedly denying any say to devolved administrations. Despite reassurances from cabinet minister David Davis, the UK’s departure from the EU will likely face many more such episodes from pro-remain Sturgeon and Jones.

A third front of opposition to Brexit has been opened by big business. The British Chamber of Commerce and the Institute for Directors have pushed Theresa May’s government for more clarity regarding the Brexit process, and the importance of avoiding a “cliff-edge” upon expiration of the 2-year transition period triggered in March. Certainty is crucial, but clear pressure is mounting from industry giants not to change the status quo –the very purpose of last year’s Brexit vote.

A fourth, ongoing front against Brexit is from advocacy groups within civil society. Last year’s court challenge of the government’s authority to trigger Article 50, and the persistent efforts of former Prime Minister Tony Blair to slow or stop the UK’s departure from the EU continue to erode meaningful debate on how best to carry out Brexit.

If Theresa May and her government are serious about carrying out the largest democratic mandate in British history, they need to do three things. First, they need to negotiate with the EU in good faith. Taking the first steps on EU citizens’ rights, adopting a constructive, realistic approach to deciding Britain’s share of EU debts, and ensuring the border in Ireland remains open (regardless of what the EU decides to do on its side) will not only give the UK the moral high ground, but also usher in the next part of Brexit talks: trade negotiations.

Second, May and her government need to prepare for the worst. In short, they should assume a “cliff-edge” scenario –involving a complete breakdown of talks– will occur, meaning a reversion to WTO trading rules. Businesses may not like this, but by signalling that no deal is guaranteed to emerge, industry has more certainty, and any future arrangement with the EU will be considered a bonus. This would likely shock the UK economy in the short term, but the ability for businesses and individuals to plan ahead would benefit all in the long term.

Third, the UK must aggressively pursue closer relationships with its international partners. Current negotiations with the EU are important, but Brussels has made clear that they preclude any further talks on a future trade relationship. It seems likely, therefore, that negotiations will start late, and be drawn out. Moreover, the EU has every reason to undermine the UK’s position, so as to discourage other member states from leaving the bloc. It is therefore quite possible they will negotiate in bad faith. As such, the UK would do far better to direct as many –if not more– resources towards trade with other nations, boosting access to far larger markets than the EU. Hints of this have already emerged, with International Trade Secretary Liam Fox opening discussions with the US, and Foreign Secretary Boris Johnson’s recent visit to New Zealand and Australia. China, Japan and Canada have also expressed interest in trade with the UK, underscoring the enormous opportunity associated with the UK’s newfound sovereignty. Of course, such deals will not be allowed so long as the UK is an EU member state, but they can be arranged for finalisation after the UK leaves, ensuring a smoother transition.

Above all, it must be clear to Britons and the world that there is no going back from last year’s referendum result. Brexit actually does mean Brexit.