(BERLIN) - European Commissioner Guenter Verheugen plans to retire in late 2009 to concentrate on "writing and teaching," he said in an interview with a German magazine released on Tuesday.

"I have had enough," Verheugen told the monthly Capital magazine in an interview to be published in full on Thursday. "By then I will be 65 years old and have 40 years of politics behind me."

By the time he steps down the centre-left German politician will have been at the European Commission for a decade, serving between 1999 and 2004 as enlargement commissioner and since then as industry commissioner. He is also commission vice-president.

Verheugen, a key ally of German Chancellor Angela Merkel, is considered to be Germany's "voice" in Brussels and is a major influence at the EU's executive body.

His predecessor as industry commissioner Martin Bangemann drew criticism in 2000 when he left to take up a well-paid post on the board of Spanish telecoms giant Telefonica.

But Verheugen does not plan to follow in Bangemann's footsteps, telling the magazine: "I believe on principle that it is wrong to take on new professional duties at retirement age."

Verheugen hit the headlines in 2006 amid allegations he promoted a female colleague with whom he had an affair. The two were photographed sunbathing naked together in Lithuania.

Text and Picture Copyright 2008 AFP. All other Copyright 2008 EUbusiness Ltd. All rights reserved. This material is intended solely for personal use. Any other reproduction, publication or redistribution of this material without the written agreement of the copyright owner is strictly forbidden and any breach of copyright will be considered actionable.