Assistant Accountant

A finance assistant performs a range of administrative and financial tasks to support the finance or accounts team of an organisation. They support the finance department by ensuring the smooth operation of day-to-day financial processes.

Purpose of the Role 

To provide comprehensive financial support to the Finance Team, ensuring accurate processing of financial transactions, maintenance of financial records, and timely delivery of financial information to support project and business objectives. 

Work closely with operational, commercial and project teams to ensure costs are accurately captured, reported and controlled.

At Costain, 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. 

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Responsibilities

Key Responsibilities 

• Process plant, material, subcontractor and supplier invoices accurately and timely. 
• Verify invoices against purchase orders and supporting documentation. 
• Investigate and resolve supplier invoice queries. 
• Assist with project close-out activities in IFS. 
• Maintain accurate project cost records and reconciliations. 
• Prepare and post journals with approvals. 
• Support accruals, prepayments and month-end processes. 
• Assist with balance sheet reconciliations and management reporting. 
• Process staff expenses in accordance with company policy. 
• Ensure compliance with financial procedures and internal controls. 
• Support audits and provide documentation when required. 
• Liaise with suppliers, site teams and project stakeholders. 

• Provide ad hoc reporting and finance administration support. 

   

  Person Specification 

• Experience in a similar role within a finance team. 
• Strong Microsoft Excel, Word and Outlook skills. 
• Excellent communication and organisational skills. 
• High attention to detail and accuracy. 
• Understanding of basic accounting principles. 

• Desirable: Experience with IFS or ERP systems and construction/project environments. 

  Personal Attributes 

• Proactive and self-motivated. 
• Strong team player. 
• Customer-focused and professional. 
• Able to prioritise workload and work to deadlines. 
• Committed to continuous improvement and development. 

Qualifications

Essential

• GCSEs including Maths and English. 
• Desirable: AAT, GNVQ or other Finance/Business qualification. 

Costain helps to improve people’s lives with integrated, leading edge, smart infrastructure solutions across the UK’s energy, water, transportation and defence markets. We help our clients improve their business performance by increasing capacity, improving customer service, safeguarding security, enhancing resilience, decarbonising and delivering increased efficiency. Our vision is to be the UK’s leading smart infrastructure solutions company. We will achieve this by focusing on blue chip clients whose major spending plans are underpinned by strategic national needs, regulatory commitments, legislation or essential performance requirements. We offer our clients leading edge solutions that are digitally optimised through the following five services which cover the whole lifecycle of their assets: future-shaping strategic consultancy; consultancy and advisory; digital technology solutions; asset optimisation and complex programme delivery. Our culture and values underpin everything we do.
CMDP is a joint venture between Costain and MWHT and delivers a range of schemes to maintain and improve Southern Water’s water supply and wastewater treatment works in the eastern half of its region (Kent & Sussex).