diff --git a/src/backend/app/db/db_models.py b/src/backend/app/db/db_models.py
index 1737b12e1e..41440b9dfc 100644
--- a/src/backend/app/db/db_models.py
+++ b/src/backend/app/db/db_models.py
@@ -18,7 +18,7 @@
 """SQLAlchemy database models for interacting with Postgresql."""
 
 from datetime import datetime
-from typing import cast
+from typing import Optional, cast
 
 from geoalchemy2 import Geometry, WKBElement
 from sqlalchemy import (
@@ -222,14 +222,15 @@ class DbTaskHistory(Base):
     action_text = cast(str, Column(String))
     action_date = cast(datetime, Column(DateTime, nullable=False, default=timestamp))
     user_id = cast(
-        int,
+        Optional[int],
         Column(
             BigInteger,
             ForeignKey("users.id", name="fk_users"),
             index=True,
-            nullable=False,
+            nullable=True,
         ),
     )
+    username = cast(str, Column(String))
 
     # Define relationships
     user = relationship(DbUser, uselist=False, backref="task_history_user")
@@ -288,17 +289,30 @@ class DbTask(Base):
     feature_count = cast(int, Column(Integer))
     task_status = cast(TaskStatus, Column(Enum(TaskStatus), default=TaskStatus.READY))
     locked_by = cast(
-        int,
-        Column(BigInteger, ForeignKey("users.id", name="fk_users_locked"), index=True),
+        Optional[int],
+        Column(
+            BigInteger,
+            ForeignKey("users.id", name="fk_users_locked"),
+            index=True,
+            nullable=True,
+        ),
     )
     mapped_by = cast(
-        int,
-        Column(BigInteger, ForeignKey("users.id", name="fk_users_mapper"), index=True),
+        Optional[int],
+        Column(
+            BigInteger,
+            ForeignKey("users.id", name="fk_users_mapper"),
+            index=True,
+            nullable=True,
+        ),
     )
     validated_by = cast(
-        int,
+        Optional[int],
         Column(
-            BigInteger, ForeignKey("users.id", name="fk_users_validator"), index=True
+            BigInteger,
+            ForeignKey("users.id", name="fk_users_validator"),
+            index=True,
+            nullable=True,
         ),
     )
 
@@ -344,7 +358,7 @@ class DbProject(Base):
         Column(
             BigInteger,
             ForeignKey("users.id", name="fk_users"),
-            nullable=False,
+            nullable=True,
             server_default="20386219",
         ),
     )
diff --git a/src/backend/app/tasks/tasks_crud.py b/src/backend/app/tasks/tasks_crud.py
index 67a02bc06a..04be2bc573 100644
--- a/src/backend/app/tasks/tasks_crud.py
+++ b/src/backend/app/tasks/tasks_crud.py
@@ -135,9 +135,8 @@ async def update_task_status(
 
         # update history prior to updating task
         update_history = await create_task_history_for_status_change(
-            db_task, new_status, db_user
+            db_task, new_status, db_user, db
         )
-        db.add(update_history)
 
         db_task.task_status = new_status
 
@@ -176,7 +175,7 @@ async def update_task_status(
 
 
 async def create_task_history_for_status_change(
-    db_task: db_models.DbTask, new_status: TaskStatus, db_user: db_models.DbUser
+    db_task: db_models.DbTask, new_status: TaskStatus, db_user: db_models.DbUser, db
 ):
     """Append task status change to task history."""
     msg = (
@@ -185,15 +184,34 @@ async def create_task_history_for_status_change(
     )
     log.info(msg)
 
-    new_task_history = db_models.DbTaskHistory(
-        project_id=db_task.project_id,
-        task_id=db_task.id,
-        action=get_action_for_status_change(new_status),
-        action_text=msg,
-        actioned_by=db_user,
-        user_id=db_user.id,
+    query = text(
+        """
+        INSERT INTO task_history (
+            project_id, task_id, action, action_text,
+            action_date, user_id
+        )
+        VALUES (
+            :project_id, :task_id, :action, :action_text,
+            :action_date, :user_id
+        )
+        RETURNING *
+    """
     )
 
+    params = {
+        "project_id": db_task.project_id,
+        "task_id": db_task.id,
+        "action": get_action_for_status_change(new_status).name,
+        "action_text": msg,
+        "action_date": datetime.now(),
+        "user_id": db_user.id,
+    }
+
+    result = db.execute(query, params)
+    db.commit()
+
+    row = result.fetchone()
+
     # TODO add invalidation history
     # if new_status == TaskStatus.INVALIDATED:
     #     new_invalidation_history = db_models.DbTaskInvalidationHistory(
@@ -204,6 +222,17 @@ async def create_task_history_for_status_change(
     # TODO add mapping issue
     # if new_status == TaskStatus.BAD:
 
+    new_task_history = db_models.DbTaskHistory(
+        id=row[0],
+        project_id=row[1],
+        task_id=row[2],
+        action=row[3],
+        action_text=row[4],
+        action_date=row[5],
+        user_id=row[6],
+        username=row[7],
+    )
+
     return new_task_history
 
 
@@ -348,7 +377,7 @@ async def get_project_task_history(
     """
     query = """
         SELECT task_history.id, task_history.task_id, task_history.action_text,
-            task_history.action_date, users.username,
+            task_history.action_date, task_history.username,
             users.profile_img
             FROM task_history
             LEFT JOIN users on users.id = task_history.user_id
diff --git a/src/backend/app/tasks/tasks_schemas.py b/src/backend/app/tasks/tasks_schemas.py
index 5faf6d1912..2cf35ff19e 100644
--- a/src/backend/app/tasks/tasks_schemas.py
+++ b/src/backend/app/tasks/tasks_schemas.py
@@ -39,8 +39,8 @@ class TaskHistoryBase(BaseModel):
 class TaskHistoryOut(TaskHistoryBase):
     """Task mapping history display."""
 
-    username: str
-    profile_img: Optional[str]
+    username: Optional[str] = ""
+    profile_img: Optional[str] = ""
     status: Optional[str] = None
 
 
diff --git a/src/backend/app/users/user_routes.py b/src/backend/app/users/user_routes.py
index 059b82a90a..d8ce07efda 100644
--- a/src/backend/app/users/user_routes.py
+++ b/src/backend/app/users/user_routes.py
@@ -20,6 +20,8 @@
 from typing import List
 
 from fastapi import APIRouter, Depends, HTTPException
+from loguru import logger as log
+from sqlalchemy import text
 from sqlalchemy.orm import Session
 
 from app.db import database
@@ -83,3 +85,72 @@ async def get_user_roles():
     for role in UserRoleEnum:
         user_roles[role.name] = role.value
     return user_roles
+
+
+@router.delete("/{user_id}", response_model=dict)
+async def delete_user_account(user_id: int, db: Session = Depends(database.get_db)):
+    """Delete a user account while preserving task history references."""
+    try:
+        transaction_sql = text(
+            """
+            BEGIN;
+
+            -- Update task history to remove user references
+            UPDATE task_history
+            SET user_id = NULL
+            WHERE user_id = :user_id;
+
+            -- Update projects authored by the user
+            UPDATE projects
+            SET author_id = NULL
+            WHERE author_id = :user_id;
+
+            -- Update tasks associated with the user
+            UPDATE tasks
+            SET
+                mapped_by = CASE
+                    WHEN mapped_by = :user_id THEN NULL
+                    ELSE mapped_by
+                END,
+                locked_by = CASE
+                    WHEN locked_by = :user_id THEN NULL
+                    ELSE locked_by
+                END,
+                validated_by = CASE
+                    WHEN validated_by = :user_id THEN NULL
+                    ELSE validated_by
+                END
+            WHERE
+                mapped_by = :user_id
+                OR locked_by = :user_id
+                OR validated_by = :user_id;
+
+            -- Delete user roles
+            DELETE FROM user_roles
+            WHERE user_id = :user_id;
+
+            -- Delete organisation managers
+            DELETE FROM organisation_managers
+            WHERE user_id = :user_id;
+
+            -- Delete user
+            DELETE FROM users
+            WHERE id = :user_id;
+
+            COMMIT;
+            """
+        )
+
+        result = db.execute(transaction_sql, {"user_id": user_id})
+
+        if result.rowcount == 0:
+            raise HTTPException(status_code=404, detail=f"User ID {user_id} not found")
+
+        db.commit()
+
+    except Exception as e:
+        db.rollback()
+        log.error(f"Error occurred while deleting user {user_id}: {e}")
+        raise HTTPException(status_code=400, detail="Failed to delete user") from e
+
+    return {"message": "User deleted successfully"}
diff --git a/src/backend/migrations/009-delete-user.sql b/src/backend/migrations/009-delete-user.sql
new file mode 100644
index 0000000000..af78a5e435
--- /dev/null
+++ b/src/backend/migrations/009-delete-user.sql
@@ -0,0 +1,25 @@
+-- ## Migration to:
+-- * Enable user data deletion
+
+-- Start a transaction
+BEGIN;
+
+-- Allow user_id in task_history to be NULL
+ALTER TABLE task_history
+ALTER COLUMN user_id DROP NOT NULL;
+
+-- Add a new column username to task_history
+ALTER TABLE task_history
+ADD COLUMN username VARCHAR;
+
+-- Allow author_id in projects to be NULL
+ALTER TABLE projects ALTER COLUMN author_id DROP NOT NULL;
+
+-- Allow locked_by, mapped_by, and validated_by in tasks to be NULL
+ALTER TABLE tasks
+ALTER COLUMN locked_by DROP NOT NULL,
+ALTER COLUMN mapped_by DROP NOT NULL,
+ALTER COLUMN validated_by DROP NOT NULL;
+
+-- Commit the transaction
+COMMIT;
diff --git a/src/backend/migrations/revert/009-delete-user.sql b/src/backend/migrations/revert/009-delete-user.sql
new file mode 100644
index 0000000000..67bcc5d210
--- /dev/null
+++ b/src/backend/migrations/revert/009-delete-user.sql
@@ -0,0 +1,25 @@
+-- ## Migration to:
+-- * Revert user data deletion changes
+
+-- Start a transaction
+BEGIN;
+
+-- Disallow user_id in task_history to be NULL
+ALTER TABLE task_history
+ALTER COLUMN user_id SET NOT NULL;
+
+-- Remove the column username from task_history
+ALTER TABLE task_history
+DROP COLUMN username;
+
+-- Disallow author_id in projects to be NULL
+ALTER TABLE projects ALTER COLUMN author_id SET NOT NULL;
+
+-- Disallow locked_by, mapped_by, and validated_by in tasks to be NULL
+ALTER TABLE tasks
+ALTER COLUMN locked_by SET NOT NULL,
+ALTER COLUMN mapped_by SET NOT NULL,
+ALTER COLUMN validated_by SET NOT NULL;
+
+-- Commit the transaction
+COMMIT;