Salary: £41,500 - 97,500 per year Requirements: Strong experience in COBOL and mainframe application development Experience of OS2200 Unisys mainframe technology Proven background in supporting and maintaining mainframe operational systems Solid understanding of batch processing, JCL, and mainframe utilities Strong SQL or database scripting knowledge (mainframe or equivalent) Experience debugging, troubleshooting, and analysing complex system interactions Familiarity with structured development practices and Agile methodologies Eligible to obtain UK Security Clearance (must meet residency requirements) Experience working within large-scale, mission-critical environments (preferred) Exposure to integration between mainframe and distributed systems (preferred) Understanding of modern development and support frameworks (preferred) Ability to mentor junior team members and support continuous improvement (preferred) Experience in Public Safety/Emergency Services would be highly advantageous (preferred) Responsibilities: Identify issues and propose effective resolutions to support end users Analyse and resolve problems relating to interfaces across multiple system components Apply creativity and technical insight to deliver enhancements and new areas of functionality Technologies: COBOL Support Network SQL Security More: We are a leading technology partner with major organisations across various sectors including Financial Services, Communications, Media, Commercial, Transportation, and the Public Sector. We deliver a broad portfolio of business solutions, including consulting, systems integration, outsourcing, network services, security, and enterprise-class technologies. Our Managed Application Services function provides 24/7 support for mission-critical applications. We are seeking a skilled Mainframe Application Developer & Support Engineer to join our team based in Milton Keynes, with a hybrid working model that requires on-site attendance at least three days a week. last updated 4 week of 2026