Both UK and EU electric car manufacturers will face the extra 10% tariff when exporting across the Channel from 2024.
The charges were agreed in the Brexit deal to protect both UK and EU car industries from cheap imports. The tax can be avoided if an electric vehicle is made using at least 45% of EU or UK content. This rises to 50-60% for battery cells and packs.
But operations on both sides of the Channel are not ready, and consumers will be left paying the price, the European Automobile Manufacturers' Association (ACEA) says.
It is pressing for the rules to be postponed for three years to give carmakers time to build local EV supply chains. That could save the industry £3.75bn over the three years, the ACEA estimates.
Luca de Meo, president of the ACEA and CEO of Renault, said: "Driving up consumer prices of European electric vehicles, at the very time when we need to fight for market share in the face of fierce international competition, is not the right move.
"We will effectively be handing a chunk of the market to global manufacturers."
The UK imports 1.2 million vehicles from the EU every year and the EU is also the UK's biggest export market.
Stellantis, which owns brands including Vauxhall and Peugeot, said UK car plants will close unless the deal is renegotiated.
The UK is open to talks with the EU, with Business Secretary Kemi Badenoch "optimistic" a deal could be reached.
However, despite EU manufacturers set to be hit, the European Commission is reluctant to enter into discussions.
It said the Brexit trade deal was agreed by both sides and the so-called rules of origin aim to create a "strong and resilient battery value chain in the EU".
EU internal commissioner Thiery Breton said: "If something has been negotiated, it shouldn't be changed."
ACEA secretary general, Sigrid de Vries, said: "The European Commission doesn't want to change anything, it seems, when it comes to Brexit-related topics. It's politically very sensitive.
"We do understand it, and we are not asking to change any of these arrangements in any fundamental way."
Electric car cost
NimbleFins research found the average cost of an electric car in the UK in 2023 is about £50,000.
The 10 cheapest electric cars cost between £22,000 and £31,000, with mileage ranging between just 60 and 185.
Luxury electric vehicles are coming with the solar-charged Lightyear 0 set to cost £265,000. The Rolls Royce Spectre will set you back upwards of £350,000.
Read more about the average cost of an electric car here.
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