Cost Controller

Closing Date

2026-07-14

Job Title: Cost Controller

Location: Durrington, Worthing

Contract Type: Permanent

Hours: 37

Salary: From £45k depending on skills and experience

About the role:

The Cost controller is responsible for the end-to-end financial control of the Smart Metering Programme, ensuring accurate forecasting, reporting and governance across Opex and Capex.

What you will be responsible for:

• Maintain a single source of financial truth, reporting consistently and on time at all levels
• Capture and manage all Opex and Capex spend at a detailed level
• Provide end-to-end financial management, including tracking, reporting and analysis; purchase order and invoice processing; and finance system updates
• Coach workstream leads on forecasting and profiling spend
• Identify and report budget risks and opportunities, with clear actions and mitigations
• Month-end / period close alignment: ownership of timetable, cut-off, accruals/prepayments, and reconciliation steps (BEX Capex - FBPs post journals, this role often coordinates and validates)
• Capex governance & accounting compliance: making sure Capex vs Opex treatment is correct, evidence is retained, and approvals meet policy (useful if you’re updating BEX/SAP)
• Maintain an audit trail of budget approvals and subsequent changes.
• Change control impact on budget: formal linkage between scope change requests and budget movements (not just an audit trail of approvals).
• Vendor/contractor cost control: checking invoices against contract/SOW/milestones, rate cards, timesheets, and ensuring correct cost coding
• Data quality controls: checks on master data/cost centres/WBS, and resolving exceptions (blocked invoices, mismatched PO’s etc.)
• Contribute financial inputs to programme and governance reporting packs
• Ensure the full financial scope is captured and kept up to date
• Stakeholder cadence: running regular cost reviews with workstream leads (weekly/fortnightly), not just coaching forecasting
• Benefits/ROI linkage (light-touch): ensuring costs can be mapped to business case lines/benefits themes so reporting tells a coherent story

What you’ll bring to the role:

• Significant experience in a project finance, management accounting, or finance co-ordinator role, supporting programmes/projects
• Proven experience managing detailed Opex/Capex budgets, including actuals, forecast and variance analysis.
• Hands-on experience with purchase order and invoice processing, cost coding and resolving exceptions (e.g., blocked invoices, mismatches).
• Experience working to month-end timelines (cut-off, accruals/prepayments and reconciliations) and maintaining a clear audit trail of budget changes.
• Strong Excel skills (e.g., pivot tables, lookups, basic data modelling) and experience maintaining data quality across financial trackers.
• Experience using finance systems (e.g., SAP) and project cost structures (e.g., WBS/cost centres); experience updating Capex systems (e.g., Bex) is desirable.
• Experience partnering with Finance Business Partners and coaching non-finance stakeholders to improve forecast accuracy.
• Experience in a regulated or highly governed environment is desirable

Southern Water is at the forefront of transforming Britain’s water industry, investing significantly to enhance resilience, sustainability, and service excellence. With £7.8bn planned investment for 2025-30, this is an unparalleled opportunity to join a business committed to delivering a generational shift in the way water services are managed.

You will be joining at a time of significant change, working alongside a highly skilled leadership team with a clear vision for the future. We offer an environment where senior professionals can make a meaningful impact, influence major strategic decisions, and drive long-term value creation

"At Southern Water, we believe diverse perspectives drive innovation. If you’re passionate about making a positive impact and think you can bring value to our team, we’d love to hear from you—even if you don’t tick every box. Your unique skills and experiences could be exactly what we need."

If this role isn’t quite what you’re looking for but are keen to be contacted about opportunities at Southern Water, you can register your details here: Introduce Yourself (myworkdaysite.com- Introduce Yourself)

Our Commitment to Diversity

We welcome applicants from all backgrounds, identities, and experiences. We do not discriminate based on race, ethnicity, gender, sexual orientation, age, disability, religion, or any other protected characteristic. If you need reasonable adjustments during the recruitment process, please let us know.

Additional information:

In line with Southern Water’s security requirements, successful candidates will be required to provide evidence of their identity, eligibility to work in the UK, criminal record check (DBS) and verification of their employment and/or education history for the past three years.

Appointment to this role is subject to the successful completion of all pre‑employment checks, including security vetting.

Please note that if a candidate does not meet the required security standards or fails to pass the vetting process, Southern Water reserves the right to withdraw the offer of employment.

Some positions may also require higher levels of security vetting, which may involve providing additional documentation.