The largest legal claim of its kind in English history against more than a dozen car manufacturers has been valued as being worth at least £6 billion, the High Court has been told.

Around 1.5 million claims have been issued against 13 car manufacturers in the wake of the 2015 “dieselgate” emissions revelations.

Those taking legal action either bought, leased or otherwise acquired a diesel vehicle made by one of the companies, with most living in England and Wales but some living elsewhere in the UK.

The mass legal action centres on allegations that manufacturers tried to “cheat” emissions tests by using banned “defeat devices” on diesel vehicles made by Mercedes-Benz, Opel and Vauxhall, Nissan and Renault, Volkswagen and Porsche, Peugeot and Citroen, Jaguar Land Rover, Ford, BMW, FCA and Suzuki, Volvo, Hyundai-Kia, Toyota and Mazda.

In written submissions for a three-day hearing in London to manage the costs of the case, which began on Monday, barrister Benjamin Williams KC said: “Even if the claims were valued conservatively at c.£4,000 per claim, that would give an overall value of at least £6 billion to these proceedings.”

Mr Williams also said that the budgets for both sides already stood at over £300 million.

In December last year, a judge said the legal action was “unprecedented” in scale, with a previous hearing told that it involves more than 1,500 defendants, once dealerships are taken into account.

One manufacturer, Mercedes, is facing more than 300,000 claims alone, the earlier hearing was told.

The case is expected to run for many years, with some hearings already scheduled for 2026.

In a separate ruling in the case on Tuesday, a judge ordered French manufacturers Renault and Peugeot Citroen to hand over documents and information to law firms representing those bringing legal action.

The companies claimed at a hearing in May that a French law, known as the French Blocking Statute, would put the companies or their employees at risk of prosecution in France if they disclosed information.

In her judgment, Mrs Justice Cockerill said that there was “no real risk of prosecution in this case”.