Ambassador R Nicholas BURNS (retired). Professor, Kennedy School, Harvard University. Formerly US Under Secretary of State for Political Affairs.

Ms Jami MISCIK. CEO and Vice-chairman, Kissinger Associates.

Mr Cary A KOPLIN. Managing Director, Neuberger Berman LLC.

Mr John BELLINGER III, Partner, Arnold & Porter Kaye Scholer LLP.

Ms Anja MANUEL. Principal, Rice Hadley Gates, LLC

Mr Peter BASS. Chairman,

Mr George M NEWCOMBE. Formerly Partner, Simpson Thacher & Bartlett LLP.

The Honorable David AARON. Formerly Deputy National Security Advisor and Senior Fellow, RAND.

Mr James ARROYO OBE. Director, The Ditchley Foundation.

Ambassador William J. BURNS, President, Carnegie Endowment for International Peace. Formerly U.S. Deputy Secretary of State.

The Honorable Joseph A CALIFANO, Jr. Founder and Chair Emeritus, The National Center on Addiction and Substance Abuse at Columbia University.

Mr Robert CONWAY. Senior Director, Goldman Sachs.

Mr Edward COX. Chairman, The New York Republican State Committee.

Dr Karen DONFRIED. President, German Marshall Fund of the United States.

Mr Francis FINLAY, CMG, OBE. Chairman Emeritus, EastWest Institute

Ambassador Anthony GARDNER. Senior Advisor, Brunswick Group; Former U.S. Ambassador to the European Union (2014-2017).

Mr James F HOGE, Jr. Senior Advisor, Teneo Intelligence. Formerly Chair, Human Rights Watch.

Sir John HOLMES, GCVO, KBE, CMG. Chair, International Rescue Committee UK. Formerly Director of The Ditchley Foundation. Formerly Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator at the United Nations, New York.

Professor A E Dick HOWARD. White Burkett Miller Professor of Law and Public Affairs, University of Virginia School of Law.

Mr Reuben JEFFERY III, Non- executive Chairman, Riverstone Credit (UK) Plc; former President and Chief Executive Officer, Rockefeller & Co.; former Undersecretary of State for Economic, Energy and Agricultural Affairs.

Mr Robert G KAISER. Former Managing Editor, The Washington Post.

Ambassador Philip LADER, Partner, Nelson Mullins. Formerly US Ambassador to the Court of St James's.

Professor Theodore R MARMOR. Formerly Yale School of Management.

The Honorable Donald F McHENRY. Distinguished Professor in Practice of Diplomacy, Edmund A. Walsh School of Foreign Service, Georgetown University.

Professor Joseph NYE. Harvard University Distinguished Service Professor, John F Kennedy School of Government. Director, Council on Foreign Relations, Washington.

Ambassador Thomas PICKERING. Vice-Chairman, Hills and Company.

Dr John E RIELLY. Adjunct Professor of Political Science, Department of Political Science, Northwestern University.

Mr David SCHWIMMER. CEO, London Stock Exchange Group.

Dr Amanda SLOAT.  Robert Bosch Senior Fellow, Brookings Institution.  Formerly U.S. Deputy Assistant Secretary for Southern Europe and Eastern Mediterranean Affairs.

Ms. Julianne SMITH. Senior Advisor to the President and Director of the Asia Program German Marshall Fund; Former Deputy National Security Advisor to Vice President (2012-13).

The Honorable Strobe TALBOTT. Distinguished Fellow in Residence, the Brookings Institution

Ambassador David THORNE. Senior Advisor to the Secretary of State, U.S. Department of State 2013-2017. U.S. Ambassador to Italy and the Republic of San Marino, 2009-2013.

Dr Catherine WILLS.

Mr Casimir A. YOST. Senior Fellow, Institute for Study of Diplomacy, Georgetown University; Formerly Director, Strategic Futures Group, National Intelligence Council.