Principal Software Engineer in London

We're looking for a Principal Software Engineer to shape the technical direction of high-profile projects and lead the delivery of modern, scalable software. We use technology to create impactful, human-centred solutions that make a difference to users and organisations. We believe great engineering happens when teams collaborate, learn, and build with purpose.

You will provide hands-on technical leadership, working closely with senior stakeholders, mentoring engineers across multiple teams, and line managing a small group of engineers while helping shape our approach to software delivery, architecture, and engineering culture.

• Lead the design and development of advanced software solutions, ensuring high standards of quality, security and scalability.
• Set the technical direction for projects and influence the wider technology strategy.
• Provide line management for a group of engineers (typically up to six), supporting their career progression and ensuring they are set up for success.
• Provide technical leadership and coaching, fostering a culture of excellence, collaboration and continuous learning.
• Collaborate with senior stakeholders to translate complex business problems into elegant, robust solutions.
• Champion modern engineering practices including CI/CD, test automation and infrastructure as code.
• Foster a DevOps culture that enables teams to build, deploy and run their services confidently through automation and continuous delivery.
• Drive the evaluation and adoption of emerging technologies to improve how we deliver software.
• Lead technical due diligence during project scoping, bids and new opportunities.
• Represent the engineering function in strategic discussions, influencing our technology roadmap.
• Anticipate and manage project risks, helping teams navigate complex technical challenges.

• Extensive experience in software engineering, with a focus on large-scale, complex systems.
• Passion for learning new technologies and helping others do the same.
• Proven track record of leading software architecture design and strategic technology initiatives.
• Strong expertise in cloud platforms, microservices and modern software development practices.
• Experience with direct line management and mentoring junior to senior engineers.
• Excellent communication skills. Ability to communicate complex technical concepts clearly to both technical and non-technical stakeholders.
• Experience working in a consultancy environment, managing client relationships at a senior level.
• Experience delivering government or public sector projects.
• Eligible for (or holding) SC security clearance.
• Knowledge of AI, machine learning, or other emerging technologies relevant to software engineering.
• Experience promoting knowledge sharing through mentoring, blogs, talks, or internal communities.

• Polyglot and fullstack expert in designing scalable, secure, and maintainable software architectures.
• Ability to set architectural standards and ensure alignment with business goals and technical strategy.
• Proven ability to lead and develop senior technical talent, providing strategic guidance and fostering growth.
• Strong influence in shaping team culture, promoting innovation, and driving high performance.
• Ability to align technical strategies with broader business objectives, ensuring technology investments deliver value.
• Skilled at identifying opportunities for technology-led innovation and efficiency improvements.
• Expertise in managing complex stakeholder relationships, both internal and client-facing.

• Purpose: Be values-driven, recognising that our client's needs are paramount. Approach client engagements with professionalism and creativity, balancing commercial and operational needs.
• Accountability: Be accountable for delivering your part of a project on time and under budget and working well with other leaders. Lead by example, promoting a culture where quality and client experience are foremost.
• Craft: Balance multiple priorities while leading high-performing teams. Navigate ambiguity and set the technical direction and approach to support positive outcomes.
• Togetherness: Collaborate effectively with others across TPXimpact. Build strong relationships with colleagues and clients.

We're a purpose driven organisation, supporting organisations to build a better future for people, places and the planet. Combining vast experience in the public, private and third sectors and expertise in human-centred design, data, experience and technology, we're creating sustainable solutions ready for an ever-evolving world.

At the heart of TPXimpact, we're collaborative and empathetic. We're a team of passionate people who care deeply about the work we do and the impact we have in the world. We know that change happens through people, with people and for people. That's why we believe in people-powered transformation.

Working in close collaboration with our clients, we seek to understand their unique challenges, questioning assumptions and building in their teams the capabilities and confidence to continue learning, iterating and adapting.

• 30 days holiday + bank holidays
• 2 volunteer days for causes that you are passionate about
• Maternity/paternity - 6 months Maternity Leave, 3 months Paternity Leave
• Life assurance
• Employer pension contribution of 5%
• Health cash plan
• Personal learning and development budget
• Employee Assistance Programme
• Access to equity in the business through a Share Incentive Plan
• Green incentive programmes including Electric Vehicle Leasing and the Cycle to Work Scheme
• Health assessments

We drive fundamental change in approaches to product and service development, delivery and technology. Our agile, multidisciplinary teams use technology, design and data to deliver better results, improving outcomes for individuals, organisations and communities.

By working in the open, in partnership with our clients, we not only transform their systems and services but also build the capability of their teams, so work can continue without us in the longer term. Our focus is sustainable change, always delivered with positive impact.

We're an inclusive employer, and we care about diversity in our teams. Let us know in your application if you have accessibility requirements during the interview.