A girl holds a placard during the "Put it to the People" march in central London, Britain, on March 23, 2019. (Xinhua/Han Yan)

Brexit has already been leaving its mark on UK-German trade for a while, says Berthold Busch, senior economist for European Integration at the German Economic Institute.

The new UK government was conducting "irresponsible politics" by ignoring such negative developments and instead, UK policy continued to pursue its strategy of "whatever the cost," added Busch.

BERLIN, Aug. 21 (Xinhua) -- The Federation of German Industries (BDI) spoke out on Wednesday against renegotiating the agreement between the European Union (EU) and the United Kingdom (UK).

"The UK Prime Minister's demand that the withdrawal agreement be reopened is irresponsible," said BDI Director General Joachim Lang.

The withdrawal agreement held "enormous importance for the German economy," Lang stressed.

German companies relied on "as little friction as possible in foreign trade, stable conditions at the external borders and security in matters relating to workers," added Lang.

Britain's new Prime Minister Boris Johnson gives a speech at 10 Downing Street in London, Britain on July 24, 2019. (Xinhua/Han Yan)

Lang emphasized that German industry supported the the government and European Commission in standing by the negotiated treaty, and urged Brussels and London to "set the right course in order to avert the threat of hard Brexit."

Brexit has already been leaving its mark on UK-German trade for a while, according to Berthold Busch, senior economist for European Integration at the German Economic Institute.

The Institute found that while German exports of goods to the EU rose by more than 12 percent between 2015 and 2018, its exports to the UK fell by 7.8 percent.

The decline was particularly pronounced for motor vehicles and pharmaceutical products, which "suggests that the value chains in these particularly closely interwoven branches of industry are already being restructured at the expense of the United Kingdom," Busch said.

A painted mural by British graffiti artist Banksy depicts a workman chipping away at one of the stars on an EU themed flag in Dover, Britain. (Xinhua/Han Yan)

The new UK government was conducting "irresponsible politics" by ignoring such negative developments and instead, UK policy continued to pursue its strategy of "whatever the cost," said Busch.

Lang noted that during this "sensitive phase, the existing concerns in the economy should be exacerbated. Our companies now have no choice but to continue to prepare for a hard Brexit on 31 October."

Only the European Commission could ensure that internal market rules would be respected at the Irish border in the long-term, which would require a backstop to avoid border posts between Northern Ireland, which is part of the UK, and the EU state of Ireland.

These comments were made as UK Prime Minister Boris Johnson is to meet German Chancellor Angela Merkel in Berlin on Wednesday evening.

Johnson had made a public commitment to lead Britain out of the EU on Oct. 31 with or without an agreement.

Demonstrators protest during the "Put it to the People" march in central London, Britain, on March 23, 2019. (Xinhua/Han Yan)