# Sealed AI predictions, study 1: UK Christmas ads 2026

Kesterley. https://kesterley.com/predictions/

On the day each UK Christmas ad comes out, three AI models predict how viewers will rate it. We publish only a fingerprint of the prediction that day. After System1’s final Christmas ranking we open every prediction and score it by rules fixed in advance. Anyone can check that nothing changed in between.

## The ledger

UK time, oldest first.

- 2026-10-29 10:52: Protocol locked. SHA-256 b0f193f614141e6e57be9580de738d99dc78cded0fef5ec6b824eaffa107a873
- 2026-10-29 10:56: Dr. Oetker, “Share a little Joy this Christmas”. SHA-256 2f8b08e9098b88fbdb9d721edbe41a95ce2043e6a3ba84c340976e19394234df
- 2026-10-29 10:56: Debenhams, “Christmas. For Everyone”. SHA-256 955dc9ccb23714d4cd79e0125f6fb513af26d87d7b98649030c8bbb8cefa4b11
- 2026-10-29 10:57: The Perfume Shop, “Let Love Last”. SHA-256 e9152f5a485b5c371a195daec14bcb6e69d5ac8742633bb8b1d85be2bcb44696
- 2026-10-30 14:54: Pandora, “More than a gift”. SHA-256 ca0245b818f3ff5d6b14e05863897f962dd5594ba4906a0127778c04ac811fc9
- 2026-11-01 10:09: Tesco, “Because this Christmas, every little helps”. SHA-256 3c8bf18b3e24caeff9f4659b9b5fdf84a872098261c25448b0e3cf4daaf9981f
- 2026-11-01 10:11: Sainsbury's, “Sainsbury’s big delivery.”. SHA-256 596c5b4e9d9b41c92a9981508928dfb70f3f8d5e6ce1aaaf47b210c369de0a7b
- 2026-11-01 10:12: Argos, “Argos Christmas Advert 2026”. SHA-256 1ad92291d6ce0683e5b67efdfc8e958f58e1ed10fc235504314e7fcc232cbfb7

## How it works

1. Gemini watches the ad through its official YouTube link and writes a scene-by-scene description. A second Google model, which does not predict, removes any judging words. We do not download the video.
2. Models from OpenAI, Google and Anthropic read the same description and predict the ad’s System1 Star Rating, ten times each, with web search off. Gemini also predicts from the video itself.
3. The same day we publish the SHA-256 fingerprint of the full record here and on X, and stamp it with OpenTimestamps, a free public timestamping service. The record stays sealed.
4. Within seven days of System1’s final Christmas ranking, expected in late November, we open every record and score it.

## The rules

The protocol fixes the ads, the exact prompts, the metrics and what counts as a hit before the first seal. The study script reads its prompts from the protocol and refuses to run if the file has changed. A sealed prediction is never re-run, and any change to the rules gets a new fingerprint and a line in the ledger.

Locked on 2026-10-29 10:52 UK time. Fingerprint: b0f193f614141e6e57be9580de738d99dc78cded0fef5ec6b824eaffa107a873. Read the protocol (https://kesterley.com/predictions/uk-christmas-2026/protocol.md), the exact file we fingerprinted.

## Brands we follow

- Airbnb
- Aldi
- Amazon
- Apple
- Argos
- Arsenal
- Asda
- BBC
- Baileys
- Barbour
- Boots
- Burberry
- Cadbury
- Cartier
- Chelsea FC
- Coca-Cola
- Debenhams
- Disney
- Disney+
- Dogs Trust
- Dr. Oetker
- EE
- Etsy
- Fat Face
- Fortnum & Mason
- Freemans
- GAP
- Good Housekeeping
- Google Pixel
- Greggs
- Harvey Nichols
- Heathrow
- Hotel Chocolat
- JD Sports
- John Lewis
- KFC
- LEGO
- Lidl
- Lindt Lindor
- M&S Clothing & Home
- M&S Food
- McDonald's
- Moonpig
- Morrisons
- National Trust
- Nespresso
- Ninja
- O2
- Pandora
- People's Postcode Lottery
- Sainsbury's
- Sanpellegrino
- Save the Children
- Sky
- Smyths
- Sports Direct
- Starbucks
- TK Maxx
- TUI
- Tesco
- The Perfume Shop
- Trafford Centre
- Treasure Tress
- Very
- Vodafone
- Waitrose

## Seal your own prediction

Anyone with a way to predict how ads will be rated, including testing companies, researchers and AI developers, can seal predictions for the same ads under the same rules. Send the SHA-256 fingerprint of your prediction record to hello@kesterley.com before midnight UK time on the ad’s release day, with a random string of at least 16 characters inside the record so the fingerprint cannot be guessed. We list every fingerprint with the time it arrived and, after System1’s final ranking, score every opened record by the same rules as ours. Late fingerprints are listed but not scored.

## Check a fingerprint

Remove the record’s sha256 field, write the rest with sorted keys and no spaces (RFC 8785), hash with SHA-256:

```python
import hashlib, json
record = json.load(open("prediction.json", encoding="utf-8"))
sealed = record.pop("sha256")
canonical = json.dumps(record, sort_keys=True, separators=(",", ":"), ensure_ascii=False)
print(hashlib.sha256(canonical.encode("utf-8")).hexdigest() == sealed)
```

## Who pays for this

Nobody paid for this study. No brand, testing company or AI company saw it in advance. From System1’s ranking we cite only what System1 publishes, with the source.

Cite as: Kesterley (2026). Sealed AI predictions, study 1: UK Christmas ads 2026. kesterley.com/predictions