User Experience Designer jobs in United Kingdom

Sirius Digital is a trusted provider of expertise in Software Engineering, Data Science, and AI, supporting clients in the defence, nuclear, space, and energy sectors. We specialise in software modelling and simulation, robotics and autonomous systems, as well as data science and engineering, delivering technical consultancy and innovative solutions.

We are seeking a Software Engineer who combines strong technical skills with problem-solving ability and effective communication. You will work independently or as part of small teams, helping Sirius Digital grow while advancing your own expertise. We offer a competitive benefits package and clear opportunities for rapid career progression.

• Deliver technical consultancy projects to a high standard
• Develop and implement software solutions across areas such as wargaming, simulation, autonomous systems, digital twins, and synthetic environments
• Build and sustain strong client relationships
• Apply mathematical and computational techniques to solve real-world problems, developing innovative approaches as needed

• Experience designing and delivering performant software applications, ideally within a technical consultancy environment
• Knowledge of software modelling and simulation techniques
• Ability to analyse requirements and define technical specifications
• Experience in one or more of the following: videogame engine technology (e.g., Unreal Engine, Godot), entity or event-based simulation, robotics, and autonomous systems
• Proficiency in C/C++, familiarity with Python, C#, Zig
• Willingness to learn new technologies and programming languages
• Ability to apply mathematical or statistical methods to scientific or applied challenges
• Confidence working with large codebases and understanding hardware/performance constraints
• Strong interpersonal skills for client and stakeholder engagement
• Experience preparing technical reports and presenting to customers
• Willingness to travel within the UK and work on client sites as required
• Background working with Defence Digital, DE&S, Dstl, Frontline Commands, or the UK Defence industry
• Degree in a STEM or computing discipline, or equivalent experience
• Proficiency with MS Office (Excel, PowerPoint, Word)

• Mentoring, internal and external training, and access to sector specialists and online learning
• Comprehensive benefits including a 7% pension contribution, private healthcare, life assurance, additional holiday purchase options, and an electric vehicle scheme

• Candidates must have an existing right to live and work in the UK.
• Candidates will need to undergo an internal BPSS check prior to gaining site access.
• Candidates will also need to either be willing and eligible or to undergo a Security Clearance check (SC level) or hold a current SC clearance upon starting their employment with the company. To gain SC clearance you will normally need at least 5 years’ UK residency.