Senior Software Developer (Contract) Location: Warton - Hybrid (1-2 days onsite) Rate: £44.31 per hour (Umbrella) Contract Length: 12 months IR35: Inside IR35 Overview A leading UK defence company is seeking an experienced Senior Software Developer to join a highly skilled engineering team working on mission‑critical, safety‑critical systems used by military personnel. This role involves developing and maintaining a suite of engineering support applications that enable frontline users to retrieve operational data, diagnose issues, and ensure continued system availability in demanding environments. The position offers hybrid working and the opportunity to contribute to long‑term, high‑integrity software programmes within the defence sector. The Role You will work on a mature .NET desktop application estate, contributing to both enhancement and ongoing support activities. The software environment blends established systems with opportunities for modernisation and improvement, offering technically varied and meaningful work. In addition to core desktop applications, the team also develops smaller specialist utilities, creating exposure to a range of development challenges and platforms. Key Responsibilities Analyse system and user requirements to influence software design and delivery planning Design, implement and configure new functionality with a focus on maintainable, high‑quality code Produce unit/module tests and associated software documentation Support Build, Integration and Test teams during formal qualification and verification activities Collaborate closely with multi‑disciplinary engineering teams Research and recommend new tools, technologies and development approaches Share knowledge, provide technical guidance and support continuous improvement within the team Essential Skills & Experience Strong commercial experience using C# Experience developing desktop applications with WPF and/or WinForms Experience working with or maintaining VB6 applications Solid understanding of structured software development in regulated or engineering‑led environments Desirable Experience Source control tools such as Git or ClearCase Automated testing tools (e.g. Coded UI, Rational Robot or similar) Oracle, SQL COM, .NET Interop XML (XSD/XSLT) Entity Framework Team Foundation Server / Azure DevOps Qualifications Degree in a STEM discipline or equivalent relevant industry experience For more information please contact Lauren Morley at JAM Recruitment or click apply