Senior C Engineer
Senior C Engineer
Clearance Required: SC-eligible
Duration: 6 months
Location: Telford with 2 days/week in office
IR35 Status: Mandated PAYE only
Job Description:
You will work closely with architects and delivery leads to design and implement robust Back End services, lead engineering best practices, and mentor junior developers.
This role is ideal for someone who thrives in a collaborative environment, enjoys solving complex technical challenges, and is passionate about delivering impactful public sector solutions.
Role Purpose
As a Senior Engineer, you will remediate, stabilise, and modernise applications participating in the Ingres-only Pathway-decoupling data from Ingres to target relational platforms (eg, Oracle/SQL Server) and implementing secure, supportable fixes that reduce risk ahead of March 2027. You'll collaborate with architects, DB specialists, testers, and delivery leads to plan and execute safe change in line with HMRC standards.
Key Outcomes
Risk reduction & compliance: Identify and remediate vulnerabilities, unsupported dependencies, and non-compliant patterns to meet HMRC security and data-protection expectations.
Decoupling from Ingres: Refactor data access; support migration from Ingres to the agreed target RDBMS while retaining UI where required.
Quality & Release readiness: Deliver thoroughly tested fixes and enhancements that are verifiable in SIT, E2E/UAT and OAT/NFR phases, supporting traceability and sign-off.
Knowledge transfer: Produce clear documentation and handover notes to HMRC live support teams.
Responsibilities
Analyse applications (forms, modules, class libraries, COM components) to map dependencies (ADO, ODBC, custom DLLs/OCXs) and Ingres touchpoints.
Design and implement low-risk remediation: data access abstraction, connection-string/driver changes, error-handling hardening, and performance fixes aligned to target databases.
Collaborate with DB engineers to plan and validate schema/data migration and to optimise SQL (procs/queries) post-migration.
Build and execute test plans with QA: unit/functional/regression, non-functional (reliability, performance), and defect life cycle management across SIT, E2E/UAT and OAT.
Contribute to release documentation and change approvals; support rehearsals and cutovers where needed.
Work within HMRC MU governance for security, data protection, and auditability; keep artefacts current (design notes, runbooks, KT packs).
Participate in agile ceremonies; coordinate with the Actian Exit streams (ETMP, Data Retention, Low-Code, Ingres-only) and Model Office activities.
Coach junior engineers and contribute to HMRC MU engineering community initiatives.
Essential Skills & Experience
Strong Engineering skills: VB6, Tuxedo, C, AWS preferred
Legacy remediation in regulated environments: diagnosing runtime faults, dependency drift, and security gaps; implementing safe, minimal-change fixes.
Database fluency: experience moving away from Ingres or similar RDBMS; comfort working with DBAs on schema, queries, and performance while preserving behaviour.
Quality engineering: practical test design, defect triage, and readiness for multi-phase test models (SIT/E2E/UAT/OAT).
Delivery habits: version control (Git/TFS), lightweight design documentation, and effective stakeholder communication.
Desirable
Familiarity with AI-assisted upgrade accelerators (eg, Retrofit/GitHub Copilot) and technical proving approaches used in the programme.
Experience with HMRC MU governance, SD&T/implementation forums, or Model Office validation