diff --git a/backend/app/api/routes/editor.py b/backend/app/api/routes/editor.py
index 5e09ada..6d8932c 100644
--- a/backend/app/api/routes/editor.py
+++ b/backend/app/api/routes/editor.py
@@ -49,6 +49,8 @@ from app.services.draft_guard import get_current_draft_context
 from app.services.editor_validation import (
     validate_bulk_seat_patch_references,
     validate_bulk_seat_patch_uniqueness,
+    validate_create_group_uniqueness,
+    validate_create_sector_uniqueness,
     validate_group_patch_uniqueness,
     validate_sector_patch_uniqueness,
     validate_single_seat_patch_references,
@@ -162,6 +164,12 @@ async def create_draft_sector(
         expected_scheme_version_id=expected_scheme_version_id,
     )
 
+    await validate_create_sector_uniqueness(
+        scheme_version_id=version.scheme_version_id,
+        sector_id=payload.sector_id,
+        element_id=payload.element_id,
+    )
+
     row = await create_scheme_version_sector(
         scheme_id=scheme.scheme_id,
         scheme_version_id=version.scheme_version_id,
@@ -205,6 +213,12 @@ async def create_draft_group(
         expected_scheme_version_id=expected_scheme_version_id,
     )
 
+    await validate_create_group_uniqueness(
+        scheme_version_id=version.scheme_version_id,
+        group_id=payload.group_id,
+        element_id=payload.element_id,
+    )
+
     row = await create_scheme_version_group(
         scheme_id=scheme.scheme_id,
         scheme_version_id=version.scheme_version_id,
diff --git a/backend/app/services/editor_validation.py b/backend/app/services/editor_validation.py
index 0469853..eaccb4e 100644
--- a/backend/app/services/editor_validation.py
+++ b/backend/app/services/editor_validation.py
@@ -147,6 +147,78 @@ async def validate_group_patch_uniqueness(
             )
 
 
+async def validate_create_sector_uniqueness(
+    *,
+    scheme_version_id: str,
+    sector_id: str,
+    element_id: str | None,
+) -> None:
+    rows = await list_scheme_version_sectors(scheme_version_id)
+
+    for row in rows:
+        if row.sector_id == sector_id:
+            _raise_uniqueness_error(
+                f"Sector id already exists in current draft version: {sector_id}",
+                {
+                    "code": "duplicate_sector_id",
+                    "message": "Sector id already exists in current draft version",
+                    "sector_id": sector_id,
+                    "conflict_sector_record_id": row.sector_record_id,
+                },
+            )
+
+    if element_id is None:
+        return
+
+    for row in rows:
+        if row.element_id == element_id:
+            _raise_uniqueness_error(
+                f"Sector element binding already exists in current draft version: {element_id}",
+                {
+                    "code": "duplicate_sector_element_id",
+                    "message": "Sector element binding already exists in current draft version",
+                    "element_id": element_id,
+                    "conflict_sector_record_id": row.sector_record_id,
+                },
+            )
+
+
+async def validate_create_group_uniqueness(
+    *,
+    scheme_version_id: str,
+    group_id: str,
+    element_id: str | None,
+) -> None:
+    rows = await list_scheme_version_groups(scheme_version_id)
+
+    for row in rows:
+        if row.group_id == group_id:
+            _raise_uniqueness_error(
+                f"Group id already exists in current draft version: {group_id}",
+                {
+                    "code": "duplicate_group_id",
+                    "message": "Group id already exists in current draft version",
+                    "group_id": group_id,
+                    "conflict_group_record_id": row.group_record_id,
+                },
+            )
+
+    if element_id is None:
+        return
+
+    for row in rows:
+        if row.element_id == element_id:
+            _raise_uniqueness_error(
+                f"Group element binding already exists in current draft version: {element_id}",
+                {
+                    "code": "duplicate_group_element_id",
+                    "message": "Group element binding already exists in current draft version",
+                    "element_id": element_id,
+                    "conflict_group_record_id": row.group_record_id,
+                },
+            )
+
+
 async def validate_single_seat_patch_references(
     *,
     scheme_version_id: str,