Senior Research Engineer, AI Labs

Senior ML Research Engineer £220,000 – £280,000 base · On-site · Central London

Most AI research roles sit at one of two extremes - pure academia with little real-world impact, or pure engineering with little room to think. This one sits in the narrow band between them, where the work is serious, the models are live, and the problems are genuinely unsolved.

You'll work on the core model stack - post-training, fine-tuning, alignment, evaluation - and see the results in production within weeks, not quarters. The measure of success is model performance in the real world, not benchmark scores or citation counts.

Small team. High ownership. High-calibre peers.

WHAT YOU'LL WORK ON

~ Post-training & alignmentDesigning and running SFT pipelines and applying alignment techniques - RLHF via PPO or the more direct DPO family. You understand what each approach optimises for, where each breaks down, and which to reach for given the data and objective at hand.

~ Parameter-efficient fine-tuning

Production experience with LoRA and QLoRA. You understand how rank, the alpha-to-rank scaling ratio, and target module selection interact with model behaviour.

~ Evaluation & failure diagnosis

Building eval frameworks tied to real-world outcomes. You can identify why a model is failing from first principles.

~ Training infrastructure

Owning data pipelines, distributed training runs, and model versioning end-to-end. PyTorch is your default. You've debugged a training run that wasn't converging and knew where to look.

WHAT WE NEED TO SEE

• You have taken an LLM through post-training and into a live production environment
• You can describe a specific model behaviour you improved, what you changed, and why it worked
• 5+ years in ML engineering or applied research with a clear production track record
• Deep Python across data, training, evaluation and serving - no significant gaps
• Strong academic backgrounds, provided they come with at least two years of hands-on production ML experience post-research. This is not the right first step after a PhD or from a research lab.

WHO TENDS TO BE A STRONG FIT

Senior ML engineers who have owned model quality end-to-end - the performance obsession, rigour under pressure, and instinct to optimise rather than theorise translate directly.COMPENSATION & BENEFITS

£220,000 – £280,000 base salary

Medical, dental and life insurance

Pension planReach out directly if the above describes you at View email address on click.appcast.io