A Hard Brexit is “mission impossible” and the UK could be forced to remain within the European Union’s (EU) single market, subject to unlimited mass migration, the head of Germany’s motor industry association has said.

Matthias Wissmann argued that the effects of Britain leaving the single market were so great that the UK should be made to stay inside it, against the will of much of the electorate.

“The hard Brexit preferred by Theresa May would have severe side effects”, the president of the German Association of the Automotive Industry (VDA) wrote in German newspaper Suddeutsche Zeitung Thursday.

“It remains the hope that in the upcoming exit process the realisation of the nearly insurmountable hurdles prevails. A hard Brexit is indeed a ‘mission impossible’,” he claimed, continuing:

“The aim of the talks must be: Britain should remain in the internal market and in the customs union, accept the basic freedoms and make a financial contribution to the EU budget, in return for unimpeded access to the internal market.”

The German motor industry is deeply reliant on the British market, with German cars accounting for half of all new cars registered in the UK, which imports 86 per cent of its vehicles.

However, British car production has boomed in the last five years, growing by a quarter to 1.6 million vehicles in 2015. Buyers in the rest of the EU purchase some 57 per cent of these British-made cars.

Mr. Wissmann explained why many Germans were so desperate to trap the UK in the single market.

“They are the voice of market economy, competition, as opposed to representatives of a ‘transfer union’. Without London, it would be even more difficult for Berlin in Brussels to stand up against the desires of other EU countries.”

Prime Minister Theresa May has said she will end free movement between the EU and Britain, which means taking Britain outside of the single market. However, MPs and campaigners are currently seeking to use the courts and parliament to stop her doing so.