Opex Portfolio Controller

idibu; Reading; Hybrid; GBP 39,000 - 65,000; Full time

Benefits offered by this job

Competitive salary

Holiday entitlement 26–30 days

Pension scheme

Wellbeing benefits

Job summary

Thames Water is seeking an analytical Opex Portfolio Controller to govern and analyse the Digital investment portfolio (~£100m per year). You will partner with Project/Programme Managers, PMO and leadership to drive robust budgeting, forecasting, reporting and benefits realisation.

The role focuses on governance, controls and continuous improvement across the portfolio, with hybrid work at Clearwater Court, Reading, and a full-time pattern.

Qualifications

• Experience in project accounting or project finance within a multi-project environment.
• Experience supporting CAPEX/OPEX governance, budgeting, forecasting, and month-end.
• Ability to challenge senior stakeholders with financial insight and clarity.
• Strong analytical, reporting and business partnering skills.
• Experience collaborating with PMO and project managers.

Responsibilities

• Lead Opex forecasting, budgeting, reporting and variance analysis for the Digital portfolio.
• Provide inputs for monthly reporting, annual budgeting and investment reviews.
• Identify financial risks, opportunities, trends, and performance issues.
• Support investment prioritisation and decision-making with clear analysis.
• Coordinate portfolio benefits tracking and value realisation reporting.

Skills

Project accounting

Forecasting

Financial analysis

Stakeholder management

Business partnering

Education

CIMA/ACCA/ACA

Tools

Excel

PowerPoint

SharePoint

SAP/SAC

Job description

We are looking for an analytical, commercially focused, and delivery-driven Opex Portfolio Controller to provide financial analysis, governance support, and business partnering across Thames Water’s Digital investment portfolio of approximately £100m per annum.

You will support portfolio planning, forecasting, reporting, investment governance, and benefits realisation, providing clear financial insight and constructive challenge to Project and Programme Managers, the Portfolio Finance Manager, PMO, and Digital Leadership Team. You will help ensure robust financial controls, accurate reporting, effective investment decisions, and continuous improvement across the Digital portfolio.

What you’ll do as an Opex Portfolio Controller

Digital Portfolio Finance

• Lead Opex forecasting, budgeting, reporting, and variance analysis across the Digital portfolio.
• Provide accurate financial inputs for monthly reporting, annual budgeting, and investment reviews.
• Identify financial risks, opportunities, trends, and performance issues.

Investment & Business Partnering

• Support the preparation, review, and assurance of investment business cases and funding submissions.
• Provide financial guidance, challenge, and insight to Project and Programme Managers.
• Support investment prioritisation and decision-making through clear financial analysis.

Benefits & Reporting

• Coordinate portfolio benefits tracking and value realisation reporting for the Digital Leadership Team.
• Produce clear financial and performance reporting, highlighting key risks, opportunities, and actions.
• Support regular finance and portfolio review meetings.

Governance & Continuous Improvement

• Ensure compliance with financial policies, accounting standards, CAPEX/OPEX principles, and governance requirements.
• Maintain strong financial controls and support effective portfolio assurance.
• Improve financial reporting, forecasting, processes, tools, and governance practices.

Base location

– Hybrid – Clearwater Court, Reading

Working pattern

– Full-time, Monday to Friday

What you should bring to the role

Essential Experience

• Strong Project Accounting or Project Finance experience within a complex, multi-project environment.
• Experience supporting CAPEX/OPEX governance, investment submissions, budgeting, forecasting, and month-end processes.
• Experience providing financial challenge and insight to senior stakeholders.
• Strong analytical, reporting, and business partnering skills.
• Experience working with Project and Programme Managers and PMO teams.

Essential Technical Skills & Qualifications

• Proficiency in Microsoft Excel, PowerPoint, and SharePoint.
• Strong financial analysis and data interpretation skills.
• Working knowledge of SAP, SAC, or similar finance systems.
• Understanding of CAPEX/OPEX accounting and financial controls.
• Familiarity with portfolio-level financial reporting and governance.

Desirable Experience

• Experience within IT, Digital, or large-scale transformation environments.
• Exposure to resource recharge, cost allocation, or TOTEX models.
• Experience with benefits tracking and value realisation.
• Experience supporting year-end processes.

Desirable Technical Skills & Qualifications

• CIMA, ACCA, ACA, or equivalent qualification, or working towards one.
• Understanding of capital planning and cost estimation.
• Working knowledge of Earned Value Management (EVM).

What’s in it for you?

• Competitive salary up to £65,000 per annum, depending on experience.
• Annual Leave - 26 days holiday per year, increasing to 30 with the length of service. (plus bank holidays).
• Performance-related pay plan directly linked to both company and individual performance measures and targets.
• Generous Pension Scheme through AON.
• Access to lots of benefits to help you take care of yourself and your family’s health and wellbeing, and your finances – from annual health MOTs and access to physiotherapy and counselling, to Cycle to Work schemes, shopping vouchers and life assurance.

Find out more about our benefits and perks (Please note different T&Cs apply if on secondment)

Who are we?

We’re the UK’s largest water and wastewater company, with more than 16 million customers relying on us every day to supply water for their taps and toilets. We want to build a better future for all, helping our customers, communities, people, and the planet to thrive. It’s a big job, and we’ve got a long way to go, so we need help from passionate and skilled people, committed to making a difference and getting us to where we want to be in the years and decades to come.

Learn more about our purpose and values

Working at Thames Wate

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Thames Water is a unique, rewarding, and diverse place to work, where every day you can make a difference, yet no day is the same. As part of our family, you’ll enjoy meaningful career opportunities, flexible working arrangements and excellent benefits.

If you’re looking for a sustainable and successful career where you can make a daily difference to millions of people’s lives while helping to protect the world of water for future generations, we’ll be here to support you every step of the way. Together, we can build a better future for our customers, our region, and our planet.

Real purpose, real support, real opportunities. Come and join the Thames Water family. Why choose us? Learn more.

We’re committed to being a great, diverse, and inclusive place to work. We welcome applications from everyone and want to ensure you feel supported throughout the recruitment process. If you need any adjustments, whether that’s extra time, accessible formats, or anything else, just let us know. We’re here to support and assist.

When a crisis happens, we all rally around to support our customers. As part of Team Thames, you’ll have the opportunity to sign up to support our customers on the frontline as an ambassador. Full training will be given for what is undoubtedly an incredibly rewarding experience. It’s also a great opportunity to learn more about our business and meet colleagues.