Fifteen Tory MPs from the Anglia region who were campaigning to leave the EU are backing David Cameron to stay on as Prime Minister.
They are among 84 Conservative MPs who signed a letter backing MP Cameron.
They include a number of high-profile ministers like Culture Secretary John Whittingdale and Employment Minister Priti Patel, both Essex MPs, who were prominent in the Leave campaign
The letter said: "We believe whatever the British people decide you have both a mandate and a duty to continue leading the nation implementing our policies."
Observers believe Mr Cameron would find his position seriously under threat if he proves unable to persuade the public that Britain should stay in the bloc.
In the Anglia region, 28 of the 62 Conservative MPs were on the leave side of the debate.
The fifteen MPs who have signed the letter supporting the Prime Minister
- Sir David Amess (Southend West)
- Richard Bacon (South Norfolk)
- Sir Henry Bellingam (NW Norfolk)
- James Duddridge (Rochford & Southend East)
- Mark Francois (Rayleigh & Wickford)
- Richard Fuller (Bedford)
- Rebecca Harris (Castle Point)
- John Hayes (South Holland and the Deepings)
- Chris Heaton-Harris (Daventry)
- Andrea Leadsom (South Northamptonshire)
- Priti Patel (Witham)
- Mike Penning (Hemel Hempstead)
- Will Quince (Colchester)
- Iain Stewart (Milton Keynes South)
- John Whittingdale (Maldon)