Heinrich von Pierer will resign as the supervisory board chairman of Siemens in the coming days as scandals surrounding Europe's largest engineering group claim their first scalp and reach a new level of intensity.

The departure marks an ignominious end to the career of one of Germany's leading businessmen and an adviser to two successive chancellors.

Mr von Pierer is hoping to temper the public outcry about the scandals, which have severely damaged Siemens's image and reputation, as most of the alleged events took place during his time as chief executive from 1993 to 2005. These involve alleged bribery and the alleged financing of a rival to its main union.

Mr von Pierer, who will step down at next Wednesday's board meeting, said: "I have always believed that one's duty to the company and its well over 400,000 employees worldwide must take priority over one's own interests. A personal responsibility regarding the current investigations was not the basis for my decision." His temporary successor until January as chairman of Siemens is Gerhard Cromme, head of the supervisory board at Thyssen-Krupp.

People close to Siemens said in recent days that Mr Cromme, a friend of the Siemens chairman, who also sits on Thyssen-Krupp's board, was one of the non-executive directors trying hard to persuade Mr von Pierer to resign.

It is unclear who will become the full-time chairman but a senior Siemens executive said it could be an outsider.

Mr von Pierer's resignation raises questions about how wide the fallout will be at Siemens and whether there are more allegations to come. Two former management board members and a sitting one - all of whom deny wrongdoing - have been named as suspects.

Mr von Pierer's successor as chief executive, Klaus Kleinfeld, said recently that "new, uncomfortable" details would almost certainly emerge.

Mr von Pierer denies any wrongdoing or knowledge of the scandals, as does Siemens.

Investors cheered the news, sending Siemens's shares up 3.78 per cent to €90.03 yesterday.

Analysts said many were hoping that this would draw the heat out of the scandals, but investors were most excited that without Mr von Pierer, Siemens's restructuring could be accelerated.

"This leaves the road free for Kleinfeld and he can now push ahead with his plans as he likes," said one London-based analyst.