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[ARTICLE · art-90511] src=thestack.technology ↗ pub= topic=artificial-intelligence verified=true sentiment=· neutral

How UK.gov's new AI tool is trained on "synthetic emails"

The UK government's AI and Data Readiness team has developed 'Project Kestrel', an end-to-end prototype that uses OpenAI large language models to generate 'synthetic emails' for training an email-sorting system, overcoming a common data blocker in the public sector. The Government Digital Service created 'Tiger Heron', a synthetic email generator that produces realistic emails without using live data, according to Senior Product Manager Faye Greasley, who said the approach could apply beyond email.

read1 min views1 publishedAug 10, 2026
How UK.gov's new AI tool is trained on "synthetic emails"
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One of the UK government’s latest AI projects is using OpenAI LLMs to create “synthetic emails” for training an email-sorting system, overcoming a common data blocker for public sector projects.

The government’s AI and Data Readiness team shared details of “Project Kestrel” in a gov.uk blog post recently, describing how the “end-to-end prototype” used LLMs to create a dataset it could train its central Cuckoo system on.

Senior Product Manager Faye Greasley said the Government Digital Service team created “Tiger Heron”, a synthetic email generator that produced emails appearing similar to the day-to-day communications processed by the public sector without using live data.

She said: “Access to a safe, realistic data set is one of the most common blockers to data innovation in the public sector. Tiger Heron may offer a practical model for getting past it and one that could apply well beyond email.”

Tigers, Herons, and Cuckoos

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