This claim has been made about several different public services in the UK, but it is not true. In fact, the treaty that forms the EU’s most fundamental law (TFEU article 345) explicitly protects the right for EU countries to nationalise industries, and states that no EU rules can ever constrain each country’s choice of public or private ownership. Evidence
Even leaving this specific provision to one side, EU law in any case would not prohibit a Labour government from nationalising (or renationalising) a public service previously privatised by the Conservatives. The rules only say that, if a country decides to privatise a service and put it out to tender, then it must consider tenders from across the single market.
And even then, EU law explicitly allows a nationalised industry such as the health service to operate without competition if this is in the national interest.
It’s particularly crazy to hear this myth quoted with reference to the railways. Numerous EU countries have publicly-owned railways! Have eurosceptics never been on a train in France, Germany or Italy? (To prove the point, even within the UK, Northern Ireland’s railways are publicly owned.) Evidence