One sub-plot of Brexit is the running argument about whether membership of the EU – or its single market – prevents Britain from nationalising its railways.

Public ownership of rail has become a totemic policy for the left, and the wider public has never accepted privatisation either: 60 per cent of voters support re-nationalisation, compared to just 25 per cent who are opposed, according to YouGov.

Some left-wingers are concerned that EU restrictions on state intervention limit the government’s ability to renationalise, while Remainers point out that publicly-owned rail is the norm in most of continental Europe.

The situation is actually quite complicated, and both sides in this argument have had a tendency to gloss over inconvenient facts: here I will try to explain what the EU rules mean in practice.

The first thing to say is that EU membership, clearly, does not prevent you having a state-owned national railway company. This is because the UK is the only major member state where one of these doesn't operate the vast majority of services.

From France to Portugal, Spain to Germany, Italy to Poland, passenger rail is overwhelmingly run by the country's respective version of British Rail. Unlike in the UK, these were never privatised and broken up.

The suggestion that EU state aid rules would prevent you from subsidising these companies is also wrong: Article 93 of the EU's treaty specifically exempts "the coordination of transport" from state aid regulations.

EU member states make great use of this exemption: ticket prices can be absurdly low, especially for commuters. In Belgium, where I live, train tickets are practically given away for free: a weekend six-hour round trip between Brussels and Arlon can be bought on the day for £19 return. For those over 65, there's a flat charge of £6 for a return ticket anywhere in the country.

Other EU countries are going further: Luxembourg subsidises its railways so much that it has decided there is no point in even bothering to collect fares anymore, and from the beginning of 2020 it's just going to make all of its public transport free, for everyone.

So EU rules do not prevent you having a public railway company, or from subsidising it to whatever absurd degree you fancy. But it's important to be clear what restrictions the EU does place on member states' railways: or to be precise, what restrictions it will place on them.

This is because the situation in the EU is changing: in 2016 the bloc approved a package of legislation called the Fourth Rail Package, which will come into force from 2023. This includes a series of new rules whose intention is to bring the private sector and market competition into the railways. Looking at the situation in member states now might not be a very good guide to what they will look like in a few years' time.

French TGVs are all state-owned (SNCF)

The Fourth Rail Package doesn't break up or privatise the existing public railway companies like the UK did with British Rail: but it effectively forces member states to replace some of their routes with privately operated ones, even when they don't really want to. The thinking behind the legislation is really the same as the privatisation of the UK railways: that involving the private sector will somehow subject operators to competitive pressure and improve services, or increase efficiency and reduce the subsidy needed. (British passengers may have a view on whether this is an effective approach.)

Under the Fourth Rail Package, subsidised routes will have to be put out to open tender, and private companies be allowed to bid for them in a commercial process. The existing state incumbents will also be able to bid – and in many cases they will win; in others, they will not. In some circumstances governments will still be allowed to “direct award” smaller contracts to the public companies, but only if they set binding targets on punctuality and passenger satisfaction. If the targets are missed for any reason at all, the contract must be opened up to the private sector.

Something like the public tenders set to become the norm in Europe are currently standard for rail franchises in the UK: they're not really market competition, just civil servants picking between different bids. Whether a company wins a contract does not really seem to come down to how good they are at running a railway, but rather how good they are at bidding for things – franchises in the UK have repeatedly failed to deliver on their promises and collapsed early, to be bailed out by the state.

10 most scenic rail journeys in Europe Show all 10 1 /10 10 most scenic rail journeys in Europe 10 most scenic rail journeys in Europe Naples to Sorrento, Italy The beautiful bookends of the Bay of Naples are connected by the Circumvesuviana, a partly single-track railway prone to disruption and using rolling stock almost as old as the Roman Empire. But all is forgiven as it arcs around the bay beneath the skirts of that infamous volcano, Vesuvius. You can alight to explore this rumbling giant, or the cities that it devastated: Pompeii and the much less visited and more rewarding Herculaneum. Stay on the line to Sorrento and you discover one of Italy’s most indulgent resorts, itself a scenic wonder. Getty 10 most scenic rail journeys in Europe Hendaye, France, to San Sebastian, Spain From a station on the French side of the Franco-Spanish border, the narrow-gauge line steals across the river that makes the frontier, and then carves a course close to the Basque Coast – with a wide-screen vision of mountains, villages and the spectacular shoreline, before ending the journey in arguably Spain’s most glorious city. Getty 10 most scenic rail journeys in Europe St Moritz to Zermatt, Switzerland The Glacier Express is the slowest “express” train in Europe, taking eight hours between these mountain resorts. The line between them owes its existence to an influx of wealthy tourists in the early 20th century, lured by the spectacular landscapes of the Swiss Alps. The route follows numerous gorges and the early stage of the Rhine. The engineering high point is the Landwasser Viaduct, which passes 213 feet over the Landwasser River before disappearing into a tunnel in the adjacent cliff. The altitudinal high point is the Oberalp Pass, where the line reaches a height of 6,670 feet. Getty 10 most scenic rail journeys in Europe Prague, Czech Republic, to Vienna, Austria Modern expresses use the historic line between the Czech and Austrian capitals, through deep valleys and across high moorland. While experiencing a slice of 19th-century Europe beyond the windows, you can enjoy free wifi and draught beer on tap. As you cross the near-invisible international frontier at high speed, toast the collapse of the Iron Curtain three decades ago. Getty 10 most scenic rail journeys in Europe Howth to Dun Laoghaire, Ireland The Dart (Dublin Area Rapid Transit) railway through the Irish capital is a humdrum suburban train that happily fringes Dublin Bay, connecting two fine coastal towns and giving a new perspective as it slices through the city centre. All yours in return for an investment of under €5 and under an hour. Getty 10 most scenic rail journeys in Europe Fort William to Mallaig, Scotland Scotland has so many superb rail journeys that it could fill all 10 spots. Many contend that the West Highland Line north from Glasgow over the wilds of Rannoch Moor to Fort William is the most spectacular. But the continuation to Mallaig is even more impressive. It offers views of Ben Nevis, the UK’s highest mountain, as the train rumbles north and west parallel to the historic “Road to the Isles”. Pause at Glenfinnan for a walk to the viaduct that features in Harry Potter, or to stay the night in a vintage railway carriage. Watch the mesmerising scenery towards the raw edge of mainland Scotland – and, from Mallaig, the ferry to southeast Skye and the end of the world. Getty 10 most scenic rail journeys in Europe Villefranche to Latour-de-Carol, France France has Europe’s original high-speed rail network, but I prefer some other 20th-century achievements – most of all this absurd line from the pretty town of Villefranche, inland from Perpignan, into the high Pyrenees. This narrow-gauge railway folly took 24 years to complete, and today the engineering miracles of its creation still form part of the great SNCF empire. The Petit Train Jaune (“little yellow train”, which also has flourishes of red) even has open-top carriages in summer, for an all-round vision of some of Europe’s mightiest mountains. Getty 10 most scenic rail journeys in Europe Menton to Grasse, France Among the many other great journeys in France is this classic line along the Cote d’Azur west from Menton – on the border with Italy – but then turns inland to reach the fragrant Provencal hill town of Grasse. The train makes 26 stops between the two, including subterranean Monaco, handsome Nice Ville and high-end Antibes. At Juan-les-Pins, the line runs through a faded tableau of terracotta then converges with the coast. Getty 10 most scenic rail journeys in Europe Bucharest to Constanta, Romania The former eastern bloc has a million great train journeys, such as the line of the Orient Express through Bulgaria and the steam-hauled main line services in western Poland. They are also pleasingly cheap. Best of all is the four-hour journey from the Romanian capital, paralleling the Danube through bucolic countryside to the handsome resort of Constanta on the Black Sea. Getty 10 most scenic rail journeys in Europe Moscow to St Petersburg, Russia The journey between the present and past Russian capitals has neither the scale of the Trans-Siberian nor the drama of some other railways in the world’s biggest country, such as the line that runs between the mountains and the Black Sea serving the resort of Sochi. But its beauty lies in the way that it portrays day life in rural Russia – a sequence of images of cottages, lakes and meadows, into which grim Soviet relics only occasionally intrude. You can cover the 400 miles on an express in as little as 3h30m, but I prefer to take a slower train to appreciate the nuances – and to stop off in the fine city of Novgorod. Getty

The main difference between the current situation in the UK and the situation that is unfolding in Europe is that these countries will, mostly, continue to have a state rail company, bidding for contracts against other private companies. The hope is that the prospect of losing these contracts will force state incumbents to up their game and do a better job, but they will likely run a dwindling number of services among a growing patchwork of operators.

This is the situation, whether you think it is good thing or bad thing. A UK government committed to public ownership for the whole railway could perhaps try and ignore the regulations, facing down Brussels – though as our experience with Brexit shows, we're not very good at that. Going rogue would also leave the government open to being taken to the European Court of Justice by private companies angry that they are missing out on lucrative contracts; it could also face infringement action from the Commission. Alternatively, the UK could work to try and change the EU’s rules – though it would be swimming against a very powerful tide.