# The White House told OpenAI and Anthropic to hold new AI models back from the UK — here's what that means

> The White House wants US officials to test new AI models before the UK's testers do.

*There's a UK government body whose whole job is testing powerful AI models before you ever get near them. This week, the US said it wants to look first. Here's what that actually changes.*

By The SuggestedTech Team · SuggestedTech
Canonical: https://suggestedtech.com/news/white-house-openai-anthropic-uk-ai-security-institute-explained

If you've never heard of the AI Security Institute, that's fair enough — it's a government body, not a consumer product, and it doesn't have a press office shouting about its work. But it does something that affects you directly: before a company like OpenAI or Anthropic releases a genuinely powerful new AI model to the public, this UK institute — alongside its US counterpart — is one of the places that gets to check it first for dangerous capabilities. This week, that arrangement changed, and it's worth understanding exactly how.

## What the AI Security Institute actually does

Set up by the UK government in 2023 (it was originally called the AI Safety Institute, renamed in 2025), AISI's job is to get access to powerful AI models before they go public and test them for things a company might not want to advertise: can this model help someone build a cyberweapon, assist with a biological threat, or act in ways nobody can predict or switch off. It isn't a regulator — it can't block a model from being released — but its findings feed straight into government policy, and the companies have, until now, generally cooperated voluntarily because it's good for public trust.

AISI is also, by the numbers, a serious operation: £66m a year in government funding, priority access to more than £1.5bn of UK supercomputing capacity, and over 100 technical staff, according to its own website. That matters for what follows, because the story here isn't that the UK's tester is out of its depth.

## What the White House actually asked for

Politico's Sophia Cai and Joseph Bambridge reported on 24 September 2026 that the White House's Office of the National Cyber Director asked OpenAI and Anthropic not to share their newest models with AISI until American authorities have tested them first. A British official confirmed the report to Bloomberg the next day. It isn't a law, and it doesn't stop the UK testing models forever — it changes the order in which things happen: America first, everyone else after.

> Because they're American companies and this has been our policy with every new frontier model that comes out,
> — [Politico](https://www.politico.com/news/2026/09/24/white-house-asks-openai-and-anthropic-to-hold-new-models-from-uk-testers-until-u-s-review-01091769), 2026-09-24

That's the entire official explanation, from an unnamed senior administration official. In plain English: because the companies are American, Washington believes it should look first. Whether you find that reasonable probably depends on whether you think of AI safety testing as a shared international project, or as each country protecting its own patch first and sharing what's left over.

## This already happened once

This isn't hypothetical. Anthropic released a new model, Claude Mythos 5.1, on 1 September 2026, and restricted it to a set of US organisations. On its own announcement, the company said:

> only available to a set of US organizations, though we're coordinating with the US government to expand access to a broader set of domestic and international partners as quickly as possible.
> — [Anthropic](https://www.anthropic.com/claude-fable-and-mythos-5-1), 2026-09-01

> **Info:** In plain English: AISI did not get to test this model before it launched. That's the first real-world example of the policy Politico reported, and it happened three weeks before the story broke.

## Is the UK less safe because of this?

AISI's director, Henry de Zoete, says no — the institute still has 'prerelease access to some of the world's most capable models' and tested OpenAI's newest model, GPT-6 Astra, before it came out. A UK government spokesperson backed that up, saying the institute 'continues to work closely with the US government, international partners and leading AI companies' and that safety risks 'do not stop at national borders'. Both statements are true as far as they go. What they don't fully answer is the narrower, more uncomfortable question: does the UK now see new frontier models on the same timetable as the US, or a step behind it? On the Mythos 5.1 evidence, it's a step behind — at least for that one model, at least for now.

## Why this happened now

The timing isn't a coincidence. This news broke the same week Prime Minister Andy Burnham was at the UN General Assembly in New York, pitching AISI as working 'hand in glove' with the US and the big AI labs, and calling for 'a single set of global principles and standards' on AI. President Trump, speaking at the same UN gathering, rejected that kind of coordinated approach outright, calling it a 'globalist scheme'. Two allied governments, in the same week, describing two quite different visions of how AI safety testing should work — and the model-access story is the clearest evidence yet of which vision is actually shaping what companies do.

There's a glossary worth keeping handy here, because the jargon is doing a lot of the confusion:

| Term | What it means |
| --- | --- |
| AI Security Institute (AISI) | The UK government body that tests powerful AI models for safety risks before they're released to the public |
| CAISI | Its US counterpart, inside the Commerce Department, which Washington now wants to go first |
| Prerelease access | Getting to test a model before the public can use it |
| Office of the National Cyber Director | The White House team that made this request — it usually handles cybersecurity policy, not AI safety |

What to actually watch: on 13 October, MPs on the Commons Business and Trade Committee will question OpenAI, Anthropic, Google DeepMind and Meta directly on exactly this kind of access gap, with AISI's own director appearing the same day. That hearing, not this week's headlines, is where you'll find out whether Parliament thinks a voluntary, goodwill-based testing system can survive one ally deciding to go first.

## Key takeaways

- The UK has a government body, the AI Security Institute (AISI), whose job is to test powerful AI models for dangerous capabilities before the public can use them.
- The White House has asked OpenAI and Anthropic not to give AISI their newest models until the US government has tested them first — reported by Politico on 24 September 2026.
- This has already happened once: Anthropic's newest model, Claude Mythos 5.1, launched 1 September 2026 restricted to US organisations only.
- AISI's director says the institute can still test other new models, including one from OpenAI, and the UK government says its safety work with the US carries on as before.
- Nothing about how AI models are tested has changed — what's changed is who gets to look first.

## FAQ

### What is the UK's AI Security Institute (AISI)?
A UK government body, set up in 2023, that tests powerful AI models for dangerous capabilities before they're released to the public. It isn't a regulator and can't block a release, but leading AI companies have generally cooperated with it voluntarily.

### What exactly did the White House ask for?
That OpenAI and Anthropic hold back their newest models from AISI until the US government has tested them first — reported by Politico on 24 September 2026, and confirmed to Bloomberg by a British official the next day.

### Has this affected a real AI model yet?
Yes. Anthropic's Claude Mythos 5.1, released 1 September 2026, launched restricted to US organisations only, with Anthropic saying it was still working to expand access.

### Does this mean UK safety testing has stopped?
No. AISI's director says the institute still gets early access to other models, including OpenAI's GPT-6 Astra. What's changed is the order companies release models to different governments in, not whether testing happens at all.

### Why is this happening now?
It surfaced the same week the UK was publicly pitching international AI safety cooperation at the UN, and the US was publicly rejecting the idea of shared global AI rules — two allied positions pulling in different directions.

## Sources

- [White House asks OpenAI and Anthropic to hold new models from UK testers until US review](https://www.politico.com/news/2026/09/24/white-house-asks-openai-and-anthropic-to-hold-new-models-from-uk-testers-until-u-s-review-01091769) — Politico, 2026-09-24
- [Trump Tells OpenAI, Anthropic to Withhold Models From UK Agency](https://www.bloomberg.com/news/articles/2026-09-25/trump-tells-openai-anthropic-to-withhold-models-from-uk-agency) — Bloomberg, 2026-09-25
- [Donald Trump tells OpenAI, Anthropic to withhold models from UK agency](https://www.business-standard.com/world-news/donald-trump-tells-openai-anthropic-to-withhold-models-from-uk-agency-126092501029_1.html) — Business Standard (Bloomberg), 2026-09-25
- [Introducing Claude Fable 5.1 and Claude Mythos 5.1](https://www.anthropic.com/claude-fable-and-mythos-5-1) — Anthropic, 2026-09-01
- [About the AI Security Institute](https://www.aisi.gov.uk/about) — AI Security Institute, 2026-09-26
- [OpenAI and Anthropic summoned to parliament on fears UK AI rules 'not fit for future'](https://www.cityam.com/openai-and-anthropic-summoned-to-parliament-on-fears-uk-ai-rules-not-fit-for-future/) — City AM, 2026-09-22
- [OpenAI and Anthropic could withhold new AI models from UK's AI Security Institute](https://www.itpro.com/security/openai-and-anthropic-snub-uks-ai-security-institute-on-new-model-testing) — IT Pro, 2026-09-25
- [Trump orders federal agencies to stop using Anthropic as dispute escalates](https://www.aljazeera.com/news/2026/2/27/trump-orders-federal-agencies-to-stop-using-anthropic-as-dispute-escalates) — Al Jazeera, 2026-02-27
- [Judge temporarily blocks Trump administration's Anthropic ban](https://www.npr.org/2026/03/26/nx-s1-5762971/judge-temporarily-blocks-anthropic-ban) — NPR, 2026-03-26
- [Anthropic disables Fable and Mythos AI models after U.S. government bars it from giving foreigners access](https://fortune.com/2026/06/13/anthropic-disables-fable-mythos-export-controls-national-security-threat/) — Fortune, 2026-06-13
- [Federal appeals court rules Pentagon's blacklist of Anthropic was legal](https://www.cnn.com/2026/09/25/tech/anthropic-pentagon-blacklist-dc-ruling) — CNN, 2026-09-25