diff --git a/app/models.py b/app/models.py
index eaf73396c..b9c7799bd 100644
--- a/app/models.py
+++ b/app/models.py
@@ -374,7 +374,7 @@ class Service(db.Model, Versioned):
     volume_sms = db.Column(db.Integer(), nullable=True, unique=False)
     volume_email = db.Column(db.Integer(), nullable=True, unique=False)
     volume_letter = db.Column(db.Integer(), nullable=True, unique=False)
-    consent_to_research = db.Column(db.Boolean, nullable=False, default=False)
+    consent_to_research = db.Column(db.Boolean, nullable=True)
 
     organisation = db.relationship(
         'Organisation',
diff --git a/migrations/versions/0277_consent_to_research_null.py b/migrations/versions/0277_consent_to_research_null.py
new file mode 100644
index 000000000..bd439dcd9
--- /dev/null
+++ b/migrations/versions/0277_consent_to_research_null.py
@@ -0,0 +1,71 @@
+"""
+
+Revision ID: 0277_consent_to_research_null
+Revises: 0266_user_folder_perms_table
+Create Date: 2019-03-01 13:47:15.720238
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+revision = '0277_consent_to_research_null'
+down_revision = '0266_user_folder_perms_table'
+
+
+def upgrade():
+    op.alter_column(
+        'services',
+        'consent_to_research',
+        existing_type=sa.BOOLEAN(),
+        nullable=True,
+        server_default=sa.null(),
+    )
+    op.alter_column(
+        'services_history',
+        'consent_to_research',
+        existing_type=sa.BOOLEAN(),
+        nullable=True,
+        server_default=sa.null(),
+    )
+    op.execute("""
+        UPDATE
+            services
+        SET
+            consent_to_research = null
+    """)
+    op.execute("""
+        UPDATE
+            services_history
+        SET
+            consent_to_research = null
+    """)
+
+
+def downgrade():
+    op.execute("""
+        UPDATE
+            services
+        SET
+            consent_to_research = false
+    """)
+    op.execute("""
+        UPDATE
+            services_history
+        SET
+            consent_to_research = false
+    """)
+    op.alter_column(
+        'services_history',
+        'consent_to_research',
+        existing_type=sa.BOOLEAN(),
+        nullable=False,
+        server_default=sa.false(),
+    )
+    op.alter_column(
+        'services',
+        'consent_to_research',
+        existing_type=sa.BOOLEAN(),
+        nullable=False,
+        server_default=sa.false(),
+    )
diff --git a/tests/app/service/test_rest.py b/tests/app/service/test_rest.py
index 610c01015..22208dd52 100644
--- a/tests/app/service/test_rest.py
+++ b/tests/app/service/test_rest.py
@@ -647,7 +647,7 @@ def test_update_service_sets_volumes(
 @pytest.mark.parametrize('value, expected_status, expected_persisted', (
     (True, 200, True),
     (False, 200, False),
-    ('Yes', 400, False),
+    ('Yes', 400, None),
 ))
 def test_update_service_sets_research_consent(
     admin_request,
@@ -656,7 +656,7 @@ def test_update_service_sets_research_consent(
     expected_status,
     expected_persisted,
 ):
-    assert sample_service.consent_to_research is False
+    assert sample_service.consent_to_research is None
     admin_request.post(
         'service.update_service',
         service_id=sample_service.id,