40+ Years of Experience,
Delivered Personally
We are a specialist finance and tax technology consultancy, led by two experienced tax technology consultants with deep roots in Big 4 consulting, multinational in-house finance, and the leading tax technology vendors.
Independent by Design
Osprey Consulting was founded with a clear purpose: to provide organisations with the quality of tax technology consulting found in the largest firms, but without the overhead, the complexity, or the lack of continuity that often comes with them.
When you work with Osprey, you work directly with us - Mark and Charlotte - from the first conversation through to completion. There are no handoffs to junior consultants, no account managers between you and your delivery team, and no time lost re-briefing people who were not part of your earlier conversations.
We specialise in finance and tax technology because it is where our experience sits. We have implemented many of the ONESOURCE solutions including Tax Provision, Corporate Tax, and Statutory Reporting - across dozens of organisations, built Alteryx automation workflows that have transformed manual finance processes, produced statutory accounts for large multinational groups, and held senior in-house finance and tax roles at major UK corporates.
Top 50 Firms in Tax Technology 2026 Named in the TaxTech500 Top 50, and winner of the July 2026 Tax Technology Consulting award "Delivering value from day one, without the overheads and complexity often found in larger firms."
- Our founding principle
Mark Hart
Co-founder & Director
Mark brings deep ONESOURCE platform expertise, built over a career spanning Big 4 advisory, multinational in-house tax, and senior roles at Thomson Reuters.
As Director of Solution Consulting at Thomson Reuters, Mark oversaw the consulting team for the ONESOURCE platform across Direct Tax, Indirect Tax, Statutory Reporting, and Global Trade Management, with a particular focus on data integrations. Mark also held roles in innovation, strategy, and partnerships, underlining his commitment to forward-thinking initiatives and delivering tangible results.
Mark qualified as a Chartered Accountant (FCA) and began his career at Arthur Andersen, before moving to Deloitte and subsequently into an in-house tax role at National Grid. He brings both the technical depth of a platform specialist and the commercial perspective of someone who has sat on the client side.
His particular areas of expertise are ONESOURCE Tax Provision configuration, data integration across the ONESOURCE suite, and the intersection of finance and tax technology with Alteryx automation workflows.
Career Path
Charlotte Hart
Co-founder & Director
Charlotte brings over two decades of senior tax and finance leadership experience.
Charlotte began her career at Deloitte before moving into senior in-house tax roles. Most recently, Charlotte served as Head of Tax at a large UK headquartered multinational group.
That in-house experience gives Charlotte a distinctive perspective: she understands what it means to own a tax function, to manage internal stakeholders and audit processes, and to have to justify technology investment to boards and finance directors. She brings this commercial grounding to every engagement.
Charlotte is particularly focused on process optimisation, process design, and ensuring that technology implementations are properly embedded in client workflows and teams.
Career Path
Our Approach
These are not aspirational values - they describe how we actually behave on every engagement.
Straightforward
We tell you what we think, not what you want to hear. If something is out of scope, unrealistic, or outside our expertise, we say so.
Accountable
We take ownership. There is no passing of issues down the chain - if something needs resolving, we resolve it.
Practical
Every recommendation we make is designed to be implemented, not filed. We think about your real constraints and work within them.
Collaborative
We work with your team, not around them. Knowledge transfer is a core part of every engagement, not an afterthought.
Trusted by Leading Vendors
Our partner relationships are long-standing and deep - not simply badged accreditations. We collaborate directly with Thomson Reuters, Alphatax, and Alteryx on client work.
Authorised ONESOURCE implementation partner. Mark is a former Thomson Reuters Director with deep platform knowledge across Tax Provision, Corporate Tax, and Statutory Reporting.
Established partner relationship with Alphatax (formerly Tax Systems), specialists in corporation tax compliance software and global tax provisioning for large organisations and professional services firms. Products include Tax Proof and AlphataxCT.
Registered Alteryx Solution Provider delivering workflow automation, system integrations, and process automation tailored to tax and finance functions.
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Work with us directly
Every engagement is handled personally by Mark and Charlotte - not delegated. If you would like to discuss your requirements, we would be glad to hear from you.
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