During his political career, he was a Member of the German Parliament, Parliamentary Secretary of State at the Foreign Office of Germany, European Commissioner for External Relations and Trade, European Commissioner for Research, Science and Education and Member of the British House of Lords, after he was created a life peer in 1993.
Semasa berkecimpung di dunia politik, ia menjabat sebagai anggota Parlemen Jerman, Menteri Luar Negeri Parlemen di Kementerian Luar Negeri Jerman, Komisaris Hubungan Luar Negeri dan Perdagangan Eropa, Komisaris Riset, Sains, dan Pendidikan Eropa, dan anggota House of Lords Britania Raya; ia diangkat sebagai jawatan seumur hidup pada tahun 1993.