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, 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 monthly Tax Technology Consulting award three months running: July, August and September 2026 "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.
Mark spent 11 years at Thomson Reuters, latterly as Director of Solution Consulting, overseeing 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.
For you, with you, or behind your team
Every engagement is one of three shapes, and we are flexible about which, including part way through. Most of our work is done alongside an in-house team: a project, a tax transformation that needs driving, or cover for a role you have not yet filled.
We do it for you
A full implementation or integration: scoped, built, tested and handed over running, with your team trained on it. The usual shape for a new system or a first automation.
We do it with you
You have the people but not the hours or the product knowledge. We work out the plan with your tax or finance manager, analyst or interim hire, build the first process together, and support them while they build the rest. The knowledge stays in your team.
We stand behind your team
Interim, contract or fixed-term cover for a tax or finance technology job that needs doing: a product specialist for a few months, a developer for one project, someone to drive the tax team's automation or transformation project, cover while you recruit, on-call support after go-live. No minimum team and no long contract.
Can we bring you in as an interim, contract or fixed-term tax technology resource?
Yes. We take on short-term and part-time work: a product or automation specialist for a defined piece of work, the tax automation or transformation part of a role you would otherwise fill with a twelve-month fixed-term hire, cover while you recruit, or support for a new interim or permanent hire while they get up to speed. You work with Mark or Charlotte directly, by the day or by the project, with no minimum term. We do the technology and the data; the tax compliance and the advice stay with your team and your advisers.
Do you only work with your partners' products?
No. Our partners' products are where most of our clients sit, but we build processes around wherever the data comes from and wherever it has to go: a third-party provider by API where one exists, a download where it does not, an ERP, a spreadsheet, a system we have not seen before. The same approach has automated six processes for a recruitment company that had nothing to do with tax, and built workflows for a treasury team.
If you want a conversation, we will be honest about what we can and cannot do, and we will say if a system you already have can give you what you need.
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. Solutions include Alphatax Provisioning 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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