Opex Portfolio Controller

Pertemps Thames Water; Reading; Hybrid; GBP 56,000 - 75,000; Full time

Benefits offered by this job

Competitive salary up to £65,000

26 days annual leave

Generous Pension Scheme

Cycle to Work and wellbeing benefits

Job summary

Thames Water, the UK’s largest water company, seeks an experienced Opex Portfolio Controller to deliver forecasting, reporting and investment governance for a Digital portfolio worth ~£100m annually. You will partner with Project/Programme Managers and the PMO to drive value realisation and continuous improvement.

The role offers hybrid working with Reading-based base location, a salary up to £65,000 depending on experience, and a comprehensive benefits package including pension and health

Qualifications

• Strong project accounting or project finance experience within a 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.

Responsibilities

• 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.
• 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.
• 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.
• 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.

Skills

Project accounting

Financial analysis

Stakeholder engagement

Business partnering

Forecasting

Education

CIMA/ACCA/ACA or equivalent

Tools

SAP

SAC

Job description

This full-time Opex Portfolio Controller post in Reading suits a commercially minded finance professional. Based at Thames Water, the holder supplies analysis, governance support and business partnering across a Digital investment portfolio worth roughly £100m each year. Duties span planning, forecasting, reporting, investment governance and benefits realisation, with constructive challenge offered to Project and Programme Managers, the PMO, the Portfolio Finance Manager and senior leaders. The controller safeguards financial controls, sharpens reporting accuracy and informs sound investment choices, while driving continuous improvement.

Salary reaches £65,000, dependent on experience, reflecting the seniority of this position and the breadth of accountability involved.

What you’ll do as an Opex Portfolio Controller

• 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.

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.

Working at Thames Water

Working at 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?

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 help and support.

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.