Data Wrangler

6-MONTHS £400 PER DAY - INSIDE IR35 HYBRID - LONDON

This is an exciting opportunity for a highly analytical and detail-driven Data Wrangler to support a major forensic data analytics project. You'll be working with a specialist team to ingest, clean, and compare massive datasets from multiple complex systems - some sources containing hundreds of millions of records. The ideal candidate will thrive in ambiguity, work independently, and apply a forensic lens to messy, unstructured operational data.

You'll be working with a globally recognised advisory firm, known for its work in forensic investigations, compliance, and financial disputes. This team operates in a highly confidential environment, supporting projects with national-level visibility. You'll be joining a collaborative, focused, and expert-led group engaged on a high-stakes piece of work.

You'll play a hands-on role working with data received from external clients-often incomplete, inconsistent, or raw. Your job is to wrangle that data into usable form, run forensic-level comparisons, and support reporting back to clients. You'll work in a secure VDI environment and must be comfortable navigating complex and sensitive data.

Key responsibilities include:

• Ingesting and transforming large datasets (100M+ rows), from Oracle, SQL Server, and flat files (CSV, XML).

• Writing and reviewing SQL and Python (Pandas) scripts to clean and join data across multiple sources.

• Conducting forensic comparisons between data sources (e.g., matching millions of XML records to transactional logs).

• Supporting peer code reviews to ensure high quality and reduce rework.

• Working within a locked-down environment using tools like VS Code, SQL clients, and secure remote desktop environments.

• Collaborating with data consultants and forensic analysts to troubleshoot logic and ensure audit-quality outputs.

• Strong SQL (T-SQL, Oracle, or PostgreSQL) - must be comfortable with complex joins and large volumes

• Python with Pandas - mandatory for data transformation and wrangling

• Experience working with large operational databases, text files, and legacy data sources

• Strong attention to detail and a forensic mindset - ability to spot inconsistencies, gaps, and unusual data behaviour

• Prior experience in a regulated, sensitive, or secure data environment is a big plus

• Previous work in or alongside large consultancy firms

Please register your interest by sending your CV via the apply link.