UK Self Assessment deadline Jan 31, 2027: a reminder clip from photos

For the 2025 to 2026 tax year, GOV.UK says online Self Assessment returns must be submitted by 11:59pm on 31 January 2027, and the main payment deadline is the same time (GOV.UK, read 2026-10-12). A UK accountant or bookkeeper can send clients a 20-second reminder built from five photos, a bed and caption cues for $0.425 in Sume rates.

This is distinct from US tax-season clips: the UK dates, the 30 December tax-code cut-off and the 31 July second payment date are different.

Which dates go in the cues?

Use only dates on the GOV.UK page. We read three: paper returns by 11:59pm on 31 October 2026, tax-code payment requests by 11:59pm on 30 December 2026, and online returns and payment by 11:59pm on 31 January 2027. The page also lists 31 July as a second payment deadline for payments on account.

What goes in the photos and cues?

Use four seconds per photo: a desk with a laptop, a receipts folder, the practice front door, a calendar page, and a contact card. Cues: "Self Assessment: 31 Jan 2027" (0 to 8), "Send your documents by 15 Jan" (8 to 16; your own internal date), "Book a call" (16 to 20). Mark your own cut-off clearly as yours, not HMRC's. Prompt a calm, minimal instrumental bed.

How do I build it with the Sume API?

Import the photos first (POST /v1/media-imports), because Timeline only accepts files already hosted on media.sume.com. Still photos are static holds, so the fades carry the motion. Keep cues short; they sit over the photo for several seconds.

Each call returns a job. Poll GET /v1/jobs/:id/status and read GET /v1/jobs/:id/result for the video_url, then pass that URL to the next step. You can call POST /v1/timeline-1.0/plan first: it is unbilled and returns the duration and estimated cost before you render, which is a cheap way to catch a timing mistake. The placeholder URLs below are examples only.

# 1) bed: POST /v1/music-router/generate (prompt: calm minimal instrumental piano, 20-second track, no vocals) -> audio artifact
# 2) assemble five imported photos (media.sume.com URLs) over a silent spine + bed
curl -X POST https://api.sume.com/v1/timeline-1.0/render \
  -H "Authorization: Bearer $SUME_API_KEY" -H "Content-Type: application/json" \
  -H "Idempotency-Key: sa-2027-timeline-001" \
  -d '{"audio":{"mode":"silence","duration_seconds":20},
       "video":[{"source_url":"https://media.sume.com/artifacts/artf_demo/photo1.jpg","start":0,"duration":4},
                {"source_url":"https://media.sume.com/artifacts/artf_demo/photo2.jpg","start":4,"duration":4,"transition":{"type":"fade","duration":0.5}},
                {"source_url":"https://media.sume.com/artifacts/artf_demo/photo3.jpg","start":8,"duration":4,"transition":{"type":"fade","duration":0.5}},
                {"source_url":"https://media.sume.com/artifacts/artf_demo/photo4.jpg","start":12,"duration":4,"transition":{"type":"fade","duration":0.5}},
                {"source_url":"https://media.sume.com/artifacts/artf_demo/photo5.jpg","start":16,"duration":4,"transition":{"type":"fade","duration":0.5}}],
       "soundtrack":{"url":"https://media.sume.com/artifacts/artf_demo/bed.mp3","gain_db":-6,"fade_out_seconds":2}}'
# 3) burn authored cues on the finished MP4 (no speech needed)
curl -X POST https://api.sume.com/v1/video-captions \
  -H "Authorization: Bearer $SUME_API_KEY" -H "Content-Type: application/json" \
  -H "Idempotency-Key: sa-2027-captions-001" \
  -d '{"video_url":"https://media.sume.com/artifacts/artf_demo/timeline.mp4","style":"slam","cues":[{"text":"Self Assessment: 31 Jan 2027","start":0,"end":8},{"text":"Send documents by 15 Jan","start":8,"end":16},{"text":"Book a call","start":16,"end":20}]}'

What does the 20-second version cost on Sume?

The photos are yours, so there is no image or video generation line. Rates come from the Sume docs: Music 1.0 and Music Router charge $0.125 per generation, Timeline 1.0 charges $0.10 per ceil(output minute), and a standalone caption job is $0.20. Check GET /v1/catalog, the live catalog, before you budget. This is not tax advice, and the clip should send readers to GOV.UK for their own deadline.

When is this the wrong approach?

A photo slideshow with cues is the cheap, fast option. It is not the right tool for every job.

• Your clients need personal tax advice: a promo clip cannot replace it.
• You file for people with a different tax year or country: the dates here are the UK 2025 to 2026 year only.
• You need to explain penalties: link to the GOV.UK penalties page rather than quoting amounts in a 20-second clip.