Crucially, the Whitehall assessment said this kind of opposition to free-trade deals is growing across Europe.

It could even affect plans for a high-profile transatlantic trade deal between the EU and the United States, the report said.

It warned that France and other countries have been trying to water down the proposed agreement between Europe and five South American countries, the so-called “Mercosur” group – Argentina, Brazil, Paraguay, Uruguay, and Venezuela.

The Government believes this deal would generate £2.5 billion a year for Britain by reducing tariffs and reforming quotas to open up trade between Europe and Latin America in beef, chicken, plant-based fuels, cars, medical drugs, and services such as banking.

Andrea Leadsom, the pro-Brexit energy minister, said: “The EU’s record at putting free trade deals in place is weak and getting worse.”

Priti Patel, the employment minister, said EU membership meant the British economy was being “tied to a sinking ship”.

She said: “Being a member of the EU has rendered us powerless to reach our own trade deals and these missed trading opportunities are costing our economy money, jobs and growth.”

A No 10 source said: “Independent experts … have warned that Britain will be rocked by a massive economic shock and risks recession if we take a leap in the dark and leave the EU. British businesses get huge benefits from having access to the EU single market of 500million people – three million jobs are linked to the EU. On top of that, firms across the UK can take advantage of the EU’s trade deals with more than 50 countries around the world – and we would lose access to every single one of those deals if we leave, doing even more damage to our economy.”