The British Chamber of Commerce in Germany has accused Prime Minister Boris Johnson of practicing a "chaotic" policy and warned of an unregulated exit from the European Union.

"The atmosphere between companies is very bad, because everyone fears that Johnson will carry out a harsh exit from Britain without taking into account the losses," chamber executive director Andreas Meyer-Schwecrat said.

"Johnson is pursuing a chaotic policy," said Mayer-Schwecrat, adding that the British prime minister is doing nothing to facilitate the Brexit, quite the opposite. He stressed that Brexit was the best solution in his view.

"If it comes to an exit without an agreement, the British industry as well as the German will be hit hard," he warned.

"We have with Britain the fifth largest volume of trade in the world, which means Germany has huge potential losses. The Brexit agreement or a second exit referendum in Britain would be the best solution," he said.

A report by Agence France-Presse says that leaving Britain without an agreement could have heavy economic consequences, with possible shortages of food, medicine and fuel.

"This exit could also hurt Germany, whose export-driven economy is already struggling."

A report in the Sunday Times also warned of food, fuel and medicine shortages, port chaos and even possible civil unrest.

Data from the Office for National Statistics showed the economy contracted at a quarterly rate of 0.2%, the first contraction since 2012, after achieving a growth rate of 0.5% in the first quarter of this year.

Johnson, described by some as Trump of Britain for their similarities and attitudes, will meet German Chancellor Angela Merkel in Berlin on Wednesday, before meeting in Paris with the French president, who has a tough stance on Brexit.