diff --git a/DigitalLearningSolutions.Web/Controllers/SupervisorController/Supervisor.cs b/DigitalLearningSolutions.Web/Controllers/SupervisorController/Supervisor.cs
index ec0e630563..06c2b6c612 100644
--- a/DigitalLearningSolutions.Web/Controllers/SupervisorController/Supervisor.cs
+++ b/DigitalLearningSolutions.Web/Controllers/SupervisorController/Supervisor.cs
@@ -97,9 +97,13 @@ public IActionResult AddSuperviseDelegate(MyStaffListViewModel model)
             var adminId = GetAdminID();
             var centreId = GetCentreId();
             var supervisorEmail = GetUserEmail();
-            AddSupervisorDelegateAndReturnId(adminId, model.DelegateEmail ?? String.Empty, supervisorEmail, centreId);
+
+            ModelState.Remove("Page");
             if (ModelState.IsValid)
+            {
+                AddSupervisorDelegateAndReturnId(adminId, model.DelegateEmail ?? String.Empty, supervisorEmail, centreId);
                 return RedirectToAction("MyStaffList", model.Page);
+            }
             else
             {
                 ModelState.ClearErrorsForAllFieldsExcept("DelegateEmail");
@@ -121,19 +125,27 @@ public IActionResult AddMultipleSuperviseDelegates(AddMultipleSupervisorDelegate
             var adminId = GetAdminID();
             var centreId = GetCentreId();
             var supervisorEmail = GetUserEmail();
-            var delegateEmailsList = NewlineSeparatedStringListHelper.SplitNewlineSeparatedList(model.DelegateEmails);
-            foreach (var delegateEmail in delegateEmailsList)
+
+            if (ModelState.IsValid)
             {
-                if (delegateEmail.Length > 0)
+                var delegateEmailsList = NewlineSeparatedStringListHelper.SplitNewlineSeparatedList(model.DelegateEmails);
+                foreach (var delegateEmail in delegateEmailsList)
                 {
-                    if (RegexStringValidationHelper.IsValidEmail(delegateEmail))
+                    if (delegateEmail.Length > 0)
                     {
-                        AddSupervisorDelegateAndReturnId(adminId, delegateEmail, supervisorEmail, centreId);
+                        if (RegexStringValidationHelper.IsValidEmail(delegateEmail))
+                        {
+                            AddSupervisorDelegateAndReturnId(adminId, delegateEmail, supervisorEmail, centreId);
+                        }
                     }
                 }
+                return RedirectToAction("MyStaffList");
+            }
+            else
+            {
+                ModelState.ClearErrorsForAllFieldsExcept("DelegateEmails");
+                return View("AddMultipleSupervisorDelegates", model);
             }
-
-            return RedirectToAction("MyStaffList");
         }
 
         private void AddSupervisorDelegateAndReturnId(
diff --git a/DigitalLearningSolutions.Web/Helpers/CommonValidationErrorMessages.cs b/DigitalLearningSolutions.Web/Helpers/CommonValidationErrorMessages.cs
index a40a140815..1cbf50c4de 100644
--- a/DigitalLearningSolutions.Web/Helpers/CommonValidationErrorMessages.cs
+++ b/DigitalLearningSolutions.Web/Helpers/CommonValidationErrorMessages.cs
@@ -9,6 +9,8 @@ public static class CommonValidationErrorMessages
         public const string TooLongEmail = "Email must be 255 characters or fewer";
         public const string InvalidEmail = "Enter an email in the correct format, like name@example.com";
         public const string WhitespaceInEmail = "Email must not contain any whitespace characters";
+        public const string EmailsRegexWithNewLineSeparator = @"(([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)(\s*\r\n\s*|\s*$))*";
+        public const string InvalidMultiLineEmail = "Enter an email in the correct format (like name@example.com). Note: Each email address should be on separate lines";
 
         public const string PasswordRegex = @"(?=.*?[^\w\s])(?=.*?[0-9])(?=.*?[A-Za-z]).*";
         public const string PasswordInvalidCharacters = "Password must contain at least 1 letter, 1 number and 1 symbol";
diff --git a/DigitalLearningSolutions.Web/ViewModels/Supervisor/AddMultipleSupervisorDelegatesViewModel.cs b/DigitalLearningSolutions.Web/ViewModels/Supervisor/AddMultipleSupervisorDelegatesViewModel.cs
index ecb9b6623f..d8082a3147 100644
--- a/DigitalLearningSolutions.Web/ViewModels/Supervisor/AddMultipleSupervisorDelegatesViewModel.cs
+++ b/DigitalLearningSolutions.Web/ViewModels/Supervisor/AddMultipleSupervisorDelegatesViewModel.cs
@@ -1,4 +1,7 @@
-namespace DigitalLearningSolutions.Web.ViewModels.Supervisor
+using DigitalLearningSolutions.Web.Helpers;
+using System.ComponentModel.DataAnnotations;
+
+namespace DigitalLearningSolutions.Web.ViewModels.Supervisor
 {
     public class AddMultipleSupervisorDelegatesViewModel
     {
@@ -7,6 +10,9 @@ public AddMultipleSupervisorDelegatesViewModel(string? delegateEmails)
         {
             DelegateEmails = delegateEmails;
         }
+
+        [Required(ErrorMessage = "Enter an email")]
+        [RegularExpression(CommonValidationErrorMessages.EmailsRegexWithNewLineSeparator, ErrorMessage = CommonValidationErrorMessages.InvalidMultiLineEmail)]
         public string? DelegateEmails { get; set; }
     }
 }
diff --git a/DigitalLearningSolutions.Web/Views/Supervisor/AddMultipleSupervisorDelegates.cshtml b/DigitalLearningSolutions.Web/Views/Supervisor/AddMultipleSupervisorDelegates.cshtml
index b6ab91d8e0..519688fdff 100644
--- a/DigitalLearningSolutions.Web/Views/Supervisor/AddMultipleSupervisorDelegates.cshtml
+++ b/DigitalLearningSolutions.Web/Views/Supervisor/AddMultipleSupervisorDelegates.cshtml
@@ -33,7 +33,7 @@
 <form method="post" novalidate>
   <vc:text-area asp-for="DelegateEmails"
                 label="User email addresses"
-                populate-with-current-value="false"
+                populate-with-current-value="true"
                 rows="8"
                 spell-check="false"
                 hint-text="Provide the work email address of each member of staff to add to your supervision list on a separate line."