Tax Investigations Manager: Lead Enquiries & Disputes in London

At Simmons Gainsford, we are a forward-thinking accountancy firm, renowned for delivering high-quality tax, consulting, and audit services to privately owned companies and high-net-worth individuals. We partner with a diverse range of clients, helping them navigate complex financial management and compliance challenges. With a client‑centric approach, we provide tailored solutions to meet their unique needs, building long‑term relationships based on trust and expertise.

We are seeking an experienced Tax Investigations Manager to assist with developing our Tax Investigations offering. This is an exciting opportunity for an experienced tax investigations specialist to take ownership of an established area of work, manage a varied portfolio of cases, and play a key role in growing the service line within the firm.

This role will initially involve taking responsibility for all existing investigations and dispute resolution matters, acting as the primary point of contact for clients and HMRC. Over time, you will work closely with Partners to develop and expand the firm’s investigations offering, identifying opportunities across the wider client base and building a specialist team as the practice grows.

The successful candidate will combine strong technical expertise with commercial awareness and the ability to build trusted relationships with clients and colleagues.

• Take ownership of our Tax Investigations service line.
• Manage a portfolio of HMRC enquiries, investigations, voluntary disclosures, and dispute resolution matters across a range of taxes.
• Act as the primary point of contact for clients and HMRC throughout the investigation lifecycle.
• Develop and implement strategic approaches to managing enquiries and resolving disputes efficiently.
• Prepare and review technical responses, disclosures, and settlement proposals.
• Lead negotiations with HMRC to achieve favourable outcomes for clients.
• Advise clients on tax risk management, compliance issues, and potential disclosure requirements.
• Work closely with Partners and the wider Tax team to identify opportunities for investigations work across the firm’s client base.
• Support the growth of the investigations service line through internal collaboration, client relationship management, and business development activities.
• Oversee the management and progress of investigation cases, ensuring deadlines and procedural requirements are met.
• Play a key role in building and developing a specialist Tax Investigations team as the service line grows, including mentoring and supporting junior staff.
• Contribute to internal training and raise awareness of investigations work across the firm.

• CTA, ACA, ACCA or equivalent professional qualification.
• Significant experience handling HMRC enquiries, investigations, voluntary disclosures, and dispute resolution matters.
• Strong technical knowledge across UK tax regimes, including personal and corporate tax.
• Experience managing investigations directly with HMRC and advising clients through complex enquiries.
• Ability to develop investigation strategies and manage cases through to settlement.
• Commercial awareness and an interest in developing and growing a specialist service line.
• Strong relationship management skills, with the ability to build trust with clients and internal stakeholders.
• Experience mentoring or managing junior staff.
• Excellent written and verbal communication skills.
• Strong organisational skills and the ability to manage multiple complex cases simultaneously.

At Sumer, we know everyone’s journey is different. That’s why we’re committed to fairness, removing barriers, and giving people the support they need to do their best work. If you need any support during the hiring process, just let us know.

Our values represent what matters most to us and guide how we work every day:

• We Shine Together
• We Do the Right Thing
• We Make It Count

We know diverse teams make us stronger. That’s why we’re creating an inclusive workplace where everyone belongs and differences are valued and celebrated.