Von Pierer’s brown eyes glint with glee at the question. “I think ‘Neutron Heinrich’ would not have been very helpful, eh?” he says, leaning over the table. “If you have 160,000 employees in Germany, you have a certain responsibility to them. You can’t just talk about it on a Sunday morning when you go to church . . .”

The Siemens boss, rated by many as the most influential European business leader of the past decade, steps down on Thursday, taking the part-time role of chairman of the company’s supervisory board. He hands on a hugely successful electronics group — a turnover of €75 billion (£52 billion) and profits of €3.4 billion — but one that is still, to its critics, too big, too slow and too ill-fitting to be kept together for long.

Trains, medical equipment, power stations, light bulbs, mobile phones — Siemens makes them all, and operates in 190 countries worldwide. But with more than a third of its 430,000 global workforce still in Germany, how can it compete on costs with faster- moving rivals?

Von Pierer, who turns 64 this week, shrugs when you put it to him. He has heard it all before — and just in case you think he hasn’t taken it in, he has now itemised the issues facing Siemens in a surprisingly frank commentary in his final annual report. The future shape of the business, customer and employee orientation, global presence, financial management, innovation: all will need to be addressed, he writes. Without constant change, Siemens will wither and die.

That’s quite a parting gift for his youthful successor, 47-year-old Klaus Kleinfeld, the man who has to decide immediately what to do with Siemens’s most pressing problem: its loss- making mobile-phone arm. Sell it? Merge it? Perhaps we will know on Thursday, when von Pierer hands over the reins.

Kleinfeld, keen to make an impression, is expected to accelerate the pace of change at the company, and that comes with von Pierer’s approval.

“The motto of this handover is continuity and change,” nods von Pierer. “Continuity means we keep certain values that made Siemens great over the last 150 years. But you have to accept change, and I am convinced that the speed of change will grow because the causes of globalisation will continue, and that means you have to move faster.”

Von Pierer, a politician by inclination — he nearly threw in his Siemens career early on to stand for local elections in Bavaria — is adept at moving from the light to the serious.

Tall, grey-haired, with a big head bending on thin shoulders, he is an accomplished persuader and technocrat, whose 10-point restructuring of Siemens in 1998 has left the group in better shape globally than it has been for a decade.

It wasn’t always easy, however, and he took considerable press flak in Germany early on when results faltered. Now, over his 12 years at the top, he can look back on doubled sales and trebled profits. More important, he has changed the feel of the company.

Alan Wood, chief executive of Siemens UK (18,000 employees), says von Pierer has turned the company from a German international firm into a true multinational. “That’s made a fantastic difference.”

Throughout that time von Pierer has tussled continuously with Germany’s powerful unions to get better productivity out of the indigenous workforce. It’s a crusade that has not made him popular in labour circles, and led to suggestions that he is still frustrated at the slow pace of change.

Times Recommends

• Lies and cover-up at MG Rover exposed by report
• High oil prices push manufacturing costs up
• Primark founder steps down as chief executive