Legal & General Investment Management's (LGIM) Dame Helena Morrissey and Citywire AA-rated Jupiter manager Alex Darwall have joined 37 senior professionals backing Brexit.
The campaign group, called Briefings for Brexit, describes itself as including both 'leavers and remainers'.
It was established by University of Cambridge economist Graham Gudgin and emeritus professor of French history Robert Tombs, in an attempt to demonstrate broad support for Brexit, the Sunday Times reported.
The group says it hopes to challenge the notion that 'only uneducated people voted for Brexit'.
Morrissey warned in 2016 that the City should work to make Brexit a success.
Speaking at a Bloomberg event, she said: ‘The City needs to recognise, if the British people voted to get sovereignty back, we cannot go in and say, "we want things to stay exactly the same, the City is more important". We have to be more subtle.
'We cannot go in all guns blazing and say "this is a disaster" – it is crying wolf and it won’t wash politically. The single market is off the table because of the freedom of movement point.'
The campaign’s co-founders said they were surprised by the level of support.
‘I've been surprised by how many people found out about it and came on board quickly,’ Gudgin told the Sunday Times.
'Together we thought, ''Gosh, we ought to be better organised than at the last referendum''. It was the whole tide of propaganda about how awful everything was, how awful everything was going to be, and we didn't believe this.
The 33 other grandees named in the campaign are:
1. Sir Paul Marshall, Marshall Wace, chairman of ARK Schools
2. Rory Maw, Bursar, Magdalen College, Oxford
3. Professor Paul Ormerod, economist at Volterra Partners, a visiting professor at the UCL Centre for Decision Making Uncertainty
4. Edmond Truell, Disruptive Capital Finance, London
5. Professor Nigel Biggar, Regius professor of moral and pastoral theology, and Canon of Christ Church, University of Oxford
6. Professor Paul Elbourne, professor of the philosophy of language, Magdalen College, Oxford University
7. James Orr McDonald post-doctoral fellow in theology, ethics and public life, Christchurch College, University of Oxford
8. Tom Simpson, philosophy of public policy, Blavatnik School, University of Oxford
9. Professor John Tasioulas, director of the Yeoh Tiong lay centre for politics, philosophy, and law, King’s College, London
10. Dr Philip Cunliffe, senior lecturer in international conflict, University of Kent
11. Sir Richard Dearlove, former head of the secret intelligence service, former master of Pembroke College, Cambridge, and chair of the trustees, University of London
12. Mr John Forsyth, former member of the Council of the Royal Institute for International Affairs and Centre of International Studies, Cambridge
13. Dr Lee Jones, reader in international politics, Queen Mary, University of London
14. Sir Peter Marshall, retired FCO, former Assistant secretary general of Commonwealth
15. Professor Gwythian Prins, emeritus research professor, London School of Economics, visiting academic professor, École Spéciale Militaire de Saint-Cyr
16. Dr Philip Towle, Emeritus Reader in International Relations, and former director of the Centre of International Studies, Cambridge
17. Sir Andrew Wood, former UK Ambassador to Yugoslavia and to Russia, and currently associate fellow, Russia and Eurasia Programme, Chatham House.
18. Lord (Maurice) Glasman is a Labour peer and political theorist and director of the Common Good Foundation
19. Professor Robert J. Jackson is distinguished professor at Carleton University Ottawa and emeritus Fletcher Jones professor of international relations at the University of Redlands, California.
20. Jonathan Rutherford, writer and political adviser, is emeritus professor of cultural studies, Middlesex University
21. Professor Richard Tuck, FBA, Frank G. Thomson professor of government at Harvard
22. Professor David Abulafia, FBA, is professor of Mediterranean history, Cambridge
23. Professor Robert Colls, professor of cultural history at De Montfort University
24. Sir Noel Malcolm, FBA, is a senior research fellow at All Souls’ College, Oxford
25. Andrew Roberts, Historian and biographer. Lehrman institute distinguished fellow at the New York Historical Society and visiting professor at the war studies department, Kings College London
26. Daniel Robinson, international history, fellow of Magdalen College, University of Oxford, formerly senior policy adviser to the minister for the cabinet office on the union and devolution in the aftermath of Brexit.
27. Professor Jonathan Rutherford, writer, political adviser and emeritus professor of cultural studies, Middlesex University and co-founder of Blue Labour
28. Peter Sarris reader in late Roman, medieval and Byzantine history, Cambridge
29. Professor David Coleman, professor of demography, University of Oxford Institute of Population Aging.
30. Pamela Dow, formerly director of strategy at the ministry of justice, now chief reform officer, Catch22
31. Joanna Williams, author and academic. Education editor of Spiked magazine. Author of Academic Freedom in an Age of Conformity (Palgrave/McMillan)
32. Ian Winter is a senior lecturer in the Department of physiology, development and neuroscience, Cambridge
33. Sir Richard Aikens, QC, is a former member of the court of appeal, and has served as Vice president of the Council of Europe’s Consultative Council of European Judges
34. Baroness (Ruth) Deech, former chair of the Human Fertilisation and Embryology Authority, and former Principal of St Anne’s College, Oxford
35. Richard Ekins, associate professor in law, St. Johns College, University of Oxford.
36. Professor Carol Harlow, QC, FBA, emeritus professor of law at the London School of Economic
37. Professor Guglielmo Verdirame, professor of international law King’s College, London