The uncertainty over the UK's Brexit strategy needs to end, the head of the German motor industry association has warned.
Matthias Wissmann said the lack of clarity could impact on German investment in the UK.
He warned that Britain is at a crossroads and needs to make up its mind which direction it intends to head in.
The president of the German Association of the Automotive Industry told the BBC: "We need, relatively soon, a clear answer. Will we have tariff and non-tariff barriers between Britain on the one hand and the European Union?
"That means a long period of uncertainties will block future investments in Britain, and that makes me really concerned.
"Therefore I hope that the British Government, at a certain crossroads within the next 12 months, decides to go for the single market and not for any other regime which would need years to discuss and negotiate.
"Five or 10 years of uncertainties would be not very positive for both sides, the European Union and Britain."