Principal Data Scientist

Company: Twelve
Apply for the Principal Data Scientist
Location: London
Job Description:

My client is a venture-backed data and analytics business. They take large, messy real-world datasets, run their own prediction models over them, and sell the output as a SaaS product to professional users around the world who rely on it for time-sensitive decisions.

They’re hiring a Principal Data Scientist to be the senior data science authority in the business. It’s a hands-on individual contributor role with no direct reports, reporting into a VP-level data leader. A lot of the work is on problems nobody has solved yet, where there’s no existing baseline and you’d be the one deciding what good looks like.

What you’d be doing

  • Setting data science direction at a product level, deciding what gets built and why
  • Owning models end to end, from research and experiment design through to production, monitoring and long-term maintenance
  • Working mostly on time-series and anomaly detection, alongside sequence-to-sequence models and stochastic optimisation
  • Improving the quality of models that are already live
  • Leading the company’s Data Science Guild, mentoring and reviewing work across the practice
  • Explaining and defending your models to traders, analysts and non-technical colleagues

What you’ll need

  • Experience operating at Staff or Principal level, with the autonomy that comes with it
  • Deep grounding in ML theory and the maths behind it
  • Fluent, production-standard Python
  • A track record of putting models into production and owning them afterwards
  • Comfort working on open-ended problems with no agreed definition of success

Nice to have

  • Knowledge of energy markets or energy systems
  • Quant trading experience, such as arbitrage, backtesting or risk
  • Hands-on work with transformer architectures, generative models or agentic AI

Compensation

The base range is £120k to £150k. Everyone in the business holds equity, and you’ll be shown a model of the projected upside during the process. The role is hybrid, with 2 days a week in the London office.

Interview Process

The interview process has three stages: a conversation with the VP of Data Production, a technical take-home, and a final discussion with the CEO.

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Posted: October 14th, 2026