THE leader of the German Chamber of Commerce has warned Angela Merkel that punishing Britain will hurt her own country's economy.A leading voice of German trade has warned that the country has a lot to lose in Brexit talks. Dr Volker Treier warned Angela Merkel, who criticised British "illusions" about Brexit yesterday, that German economy will suffer if she does not treat the UK well. The foreign trade chief of the German Chambers of Industry and Commerce said that the first signs of damage from Brexit could already be seen in the country.During a panel discussion about Brexit on German television, the host asked: "Mr Treier, will the German economy after Brexit be left running around with a black eye? Great Britain is the third biggest trade partner." Dr Treier responded: "Yes, we can already feel it. The British Pound has been devalued since the Brexit decision, it has been devalued if we go back even further. "And in the past year our exports were in the black till the Brexit decision. In the end we landed at minus three per cent. In the fourth quarter there was a decline of nine per cent."He added: "This means there is already some damage. Great Britain and the economy are helped by the weak pound at the moment. "There will be obstacles in our relationship. Great Britain will no longer be a member of the EU and therefore we will have a different type of relationship and not the same good one we have today." However, Dr Treier also warned that the UK will be the biggest victim of the break-up process.The business chief explained: "We will suffer injury but the United Kingdom will suffer bigger damage, at least with the relations to the German economy."Because of the Brexit decision there will be a decline of investment activities of German companies in Great Britain. Germany is responsible for 400,000 jobs on the island." He also insisted that the Brexit talks implement a transitional period to help local businesses cope. Others on the panel warned that Britain "has more to lose". This comes ahead of a EU summit tomorrow that will approve the bloc's negotiating strategy for Brexit discussions. The European Council President Donald Tusk has already demanded that Britain settle its finance commitments - including a £50billion bill - before talks begin.