Principal / Lead Engineer

Principal / Lead Engineer Python / Cloud / Terraform / IAM / DevOps / infrastructure-as-a-code IaC Rate: Circa £600 - £700 PD (Outside IR35), 6 Months Location: London / Hybrid x2 days We are seeking an experienced Principal / Lead Engineer to join a highly ambitious organisation building a large-scale, mission-critical data and technology platform. This is a unique opportunity to join at the earliest stages of a major programme and play a key role in shaping its technical foundations. Working closely with the CTO and a small team of senior engineers, you will lead the design and implementation of core infrastructure, establish engineering standards and practices, and make architectural decisions that will have long-term strategic impact. If you enjoy solving complex technical challenges, influencing technology strategy, and creating robust engineering foundations, this role offers an exceptional opportunity to make a lasting impact. Role & Responsibilities Technical Leadership Lead the design and implementation of foundational platform infrastructure and engineering capabilities Define architectural patterns, engineering standards, and best practices that will guide future development Partner closely with the CTO and senior stakeholders to make and document key technical decisions Promote secure-by-design principles across all aspects of platform development Establish and maintain core engineering tooling, including source control, CI/CD pipelines, infrastructure-as-code, and automated testing frameworksPlatform Engineering Design and implement identity and access management solutions with robust authentication and authorisation controls Build and manage cloud infrastructure using modern infrastructure-as-code approaches Develop audit, workflow, and operational capabilities to support governance and compliance requirements Implement networking, monitoring, and security controls for highly secure environments Evaluate and integrate appropriate open-source technologies and third-party components Contribute to the design and delivery of scalable, resilient, and maintainable distributed systemsCollaboration & Team Development Act as a senior technical contributor within a high-performing engineering team Mentor engineers and help establish a strong engineering culture as the organisation grows Collaborate with product, design, and delivery teams to ensure technology solutions align with business objectives Engage with external partners, suppliers, and stakeholders where required Essential Skills & Experience Proven experience leading or making significant contributions to complex distributed, cloud-native, or federated systems Strong software engineering expertise in Python, including backend development, automation, and infrastructure tooling Hands-on experience with at least one major cloud platform (AWS, Azure, or Google Cloud) Strong experience implementing Infrastructure as Code using tools such as Terraform or equivalent Experience designing and building authentication and authorisation systems, including modern identity standards and policy-based access controls Solid understanding of data storage architectures and the trade-offs between different storage and query patterns Experience establishing CI/CD pipelines and engineering best practices within modern software environments Ability to work effectively in fast-moving environments with evolving requirements and limited precedent Strong communication skills with the ability to explain complex technical concepts to both technical and non-technical audiences Desirable Skills & Experience Experience building secure, highly regulated, or mission-critical platforms Familiarity with federated architectures and distributed data access models Experience designing solutions with strong governance, auditability, and security requirements Knowledge of privacy-preserving technologies and secure computing environments Experience evaluating, adopting, or contributing to open-source technologies Background working within complex stakeholder environments undergoing significant transformation