diff --git a/app/main/views/add_service.py b/app/main/views/add_service.py
index 412b57a03..4fb52a377 100644
--- a/app/main/views/add_service.py
+++ b/app/main/views/add_service.py
@@ -48,7 +48,7 @@ def _create_example_template(service_id):
 @user_is_gov_user
 def add_service():
     form = CreateServiceForm(
-        organisation_type=current_user.default_organisation.organisation_type
+        organisation_type=current_user.default_organisation_type
     )
     heading = 'About your service'
 
@@ -58,7 +58,7 @@ def add_service():
 
         service_id, error = _create_service(
             service_name,
-            current_user.default_organisation.organisation_type or form.organisation_type.data,
+            current_user.default_organisation_type or form.organisation_type.data,
             email_from,
             form,
         )
diff --git a/app/models/user.py b/app/models/user.py
index 54d786e2d..ce7f76f54 100644
--- a/app/models/user.py
+++ b/app/models/user.py
@@ -205,6 +205,20 @@ class User(UserMixin):
             organisations_client.get_organisation_by_domain(self.email_domain)
         )
 
+    @property
+    def default_organisation_type(self):
+        if self.default_organisation:
+            return self.default_organisation.organisation_type
+        if self.has_nhs_email_address:
+            return 'nhs'
+        return None
+
+    @property
+    def has_nhs_email_address(self):
+        return self.email_address.lower().endswith((
+            '@nhs.uk', '.nhs.uk', '@nhs.net', '.nhs.net',
+        ))
+
     def serialize(self):
         dct = {
             "id": self.id,
diff --git a/app/templates/views/add-service.html b/app/templates/views/add-service.html
index ad7c30229..b284e972e 100644
--- a/app/templates/views/add-service.html
+++ b/app/templates/views/add-service.html
@@ -20,7 +20,7 @@
 
       {{ textbox(form.name, hint="You can change this later") }}
 
-      {% if not current_user.default_organisation.organisation_type %}
+      {% if not current_user.default_organisation_type %}
         {{ radios(form.organisation_type) }}
       {% endif %}
 
diff --git a/tests/app/main/views/test_add_service.py b/tests/app/main/views/test_add_service.py
index cbc8342bb..e6860cf2f 100644
--- a/tests/app/main/views/test_add_service.py
+++ b/tests/app/main/views/test_add_service.py
@@ -3,7 +3,7 @@ from flask import session, url_for
 
 from app.utils import is_gov_user
 from tests import organisation_json
-from tests.conftest import mock_get_organisation_by_domain
+from tests.conftest import mock_get_organisation_by_domain, normalize_spaces
 
 
 def test_non_gov_user_cannot_see_add_service_button(
@@ -62,6 +62,11 @@ def test_get_should_not_render_radios_if_org_type_known(
     assert not page.select('.multiple-choice')
 
 
+@pytest.mark.parametrize('email_address', (
+    # User’s email address doesn’t matter when the organisation is known
+    'test@example.gov.uk',
+    'test@example.nhs.uk',
+))
 @pytest.mark.parametrize('inherited, posted, persisted, sms_limit', (
     (None, 'central', 'central', 250000),
     ('central', None, 'central', 250000),
@@ -79,10 +84,13 @@ def test_should_add_service_and_redirect_to_tour_when_no_services(
     mock_create_or_update_free_sms_fragment_limit,
     mock_get_all_email_branding,
     inherited,
+    email_address,
     posted,
     persisted,
     sms_limit,
 ):
+    api_user_active.email_address = email_address
+    client_request.login(api_user_active)
     mock_get_organisation_by_domain(mocker, organisation_type=inherited)
     client_request.post(
         'main.add_service',
@@ -120,6 +128,69 @@ def test_should_add_service_and_redirect_to_tour_when_no_services(
     mock_create_or_update_free_sms_fragment_limit.assert_called_once_with(101, sms_limit)
 
 
+def test_add_service_has_to_choose_org_type(
+    mocker,
+    client_request,
+    mock_create_service,
+    mock_create_service_template,
+    mock_get_services_with_no_services,
+    api_user_active,
+    mock_create_or_update_free_sms_fragment_limit,
+    mock_get_all_email_branding,
+):
+    mocker.patch(
+        'app.organisations_client.get_organisation_by_domain',
+        return_value=None,
+    )
+    page = client_request.post(
+        'main.add_service',
+        _data={
+            'name': 'testing the post',
+        },
+        _expected_status=200,
+    )
+    assert normalize_spaces(page.select_one('.error-message').text) == (
+        'Not a valid choice'
+    )
+    assert mock_create_service.called is False
+    assert mock_create_service_template.called is False
+    assert mock_create_or_update_free_sms_fragment_limit.called is False
+
+
+@pytest.mark.parametrize('email_address', (
+    'test@nhs.net',
+    'test@nhs.uk',
+    'test@example.NhS.uK',
+    'test@EXAMPLE.NHS.NET',
+    pytest.param(
+        'test@not-nhs.uk',
+        marks=pytest.mark.xfail(raises=AssertionError)
+    )
+))
+def test_add_service_guesses_org_type_for_unknown_nhs_orgs(
+    mocker,
+    client_request,
+    mock_create_service,
+    mock_create_service_template,
+    mock_get_services_with_no_services,
+    api_user_active,
+    mock_create_or_update_free_sms_fragment_limit,
+    mock_get_all_email_branding,
+    email_address,
+):
+    api_user_active.email_address = email_address
+    client_request.login(api_user_active)
+    mocker.patch(
+        'app.organisations_client.get_organisation_by_domain',
+        return_value=None,
+    )
+    client_request.post(
+        'main.add_service',
+        _data={'name': 'example'},
+    )
+    assert mock_create_service.call_args[1]['organisation_type'] == 'nhs'
+
+
 @pytest.mark.parametrize('organisation_type, free_allowance', [
     ('central', 250 * 1000),
     ('local', 25 * 1000),