Baroness Nicholson of Winterbourne was ennobled and took her seat as a member of the House of Lords in the United Kingdom Parliament in 1997, having also served as a Member of the House of Commons and, subsequently, in the European Parliament.

She is a member of the United Kingdom Delegation to the Parliamentary Assembly of the Council of Europe and the European Security and Defence Assembly. She chairs the All-Party Parliamentary Groups for Foreign Affairs; and for Economic Development in Iraq & the Region. She is Vice-Chairman of the All-Party Parliamentary Groups on Human Trafficking; for EU Enlargement; and for Georgia; and remains an active participant in a large number of these Groups.