Julia Rampen is the digital news editor of the New Statesman, a British political magazine.

Open this photo in gallery Neil Carlton senior distillery operator works in the still house at the new Clydeside Distillery on Nov. 30, 2017 in Glasgow, Scotland. Jeff J Mitchell/GETTY IMAGES

In the classic movie Whisky Galore! a Scottish island runs out of whisky during the Second World War. Thankfully, the islanders are saved from this grim existence when a ship well-stocked with the tipple sinks close to shore. Despite the efforts of the customs and excise officer, gleeful plunder ensues.

These days, the islanders would be less worried about running dry, and more about missing an opportunity for foreign cash. Scotland exported £4.36-billion ($7.3-billion) of whisky last year, according to the Scotch Whisky Association, with the United States, France, Singapore, Germany and Spain among its top customers (Canada, the 15th largest market, imports £73-million of Scotch a year). Within Scotland, there is a thriving Scotch tourism industry – you can knock back single malt on a wildlife tour, play “guess the whisky,” or even watch a drop magically levitate.

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But now, thanks to Brexit, whisky is on the rocks – and not the icy type.

“Secret post-Brexit trade deal ‘could threaten Scotch whisky',” declared The Scotsman, a newspaper associated with the tweedier classes. “UK accused of using Scotch whisky as a bargaining chip in Brexit talks,” warned The National, a title more popular with those toasting the cause of independence. When it comes to fears about whisky, there’s a hint of protectionism, an aroma of patriotism and peaty note of worries about jobs.

In Scotland, whisky is more than just a drink – in Gaelic, it is known as uisge beatha, or the “water of life,” and it oils the wheels of Scottish society, from Burns Suppers to a neighbour dropping round for a chat. The names of whiskies themselves reflect the places they are distilled – Jura is the island where George Orwell wrote 1984, and Campbeltown lies at the end of a wild peninsula.

Scotland’s pro-independence, anti-Brexit government understands that whisky makes Scots emotional. “Distillers in the USA are already pushing to redefine ‘Scottish Whisky’ so that even those who invented it and after whom it is named will be unable to maintain its premium position,” Scotland’s Brexit negotiator, Michael Russell, thundered to The National.

While Britain remains a member of the European Union, Scotland benefits from legal recognition of Scotch’s unique “geographical indications,” which effectively bans anyone outside of the country from selling a knock-off version and calling it Scotch. It remains unclear whether the protections will be maintained with such force after Brexit, especially if Britain is negotiating trade deals with more powerful partners, such as the United States.

Less stirring, but equally important, is the threat Brexit poses to jobs. Distilleries may be more to tourist tastes, but most of the employment created by whisky lies in other parts of the production chain, such as bottling plants. Diageo, a drinks giant that owns Scotch whiskies such as Glenkinchie, Cardhu and Talisker, announced in 2017 it was cutting 100 jobs across its Scottish operations and moving some spirits production to Italy. Trade-union representatives blamed Brexit. In some bottling plants, workers report the number of production lines is reduced, and worry about the future.

The biggest threat to the whisky industry, though, is the most immediate: how to get the finest single malts to the bars of Paris, Berlin and Madrid. Since the British government has yet to get Brussels to concede to anything close to the existing single market and customs union, excise checks on goods leaving Britain seem likely. Indeed, civil servants are already drawing up plans to turn highways near the English Channel into parking lots for trucks held up by extra bureaucracy.

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With the approach of winter – the season when Scots retreat by the fire with a dram – this question is becoming more urgent. Britain is supposed to leave the EU by March 29, 2019, but Prime Minister Theresa May is struggling to win over her own MPs to back a Brexit deal, let alone the negotiators on the opposite side in Brussels. Meanwhile, there is a very real chance Britain could crash out with no plan at all. Whisky distilleries, along with all of Britain’s exporters, remain uncertain about what boxes they will have to tick in five months time.

Although many Leave voters remain so committed to Brexit that they would risk Britain’s own political union, two-thirds of Scots believe the British government is ignoring their country’s concerns on Brexit, which range from ensuring there are enough immigrant workers to staff essential services, to securing grants for universities. While Scotland remains divided between the left and right, and nationalists and unionists, the extent to which the population clinks glasses on cultural and economic priorities is often underestimated. Ms. May narrowly clung onto power in the 2017 general election, thanks in part to the election of 13 Scottish Tory MPs, who are currently lobbying hard to stop their own government hiking taxes on Scotch. If she forgets about one of their country’s biggest industries, she’ll have quite the hangover.