Analysing the "Autumn Triangle" footage from October—genuine or misidentification?

A member posted this video on Twitter last week and it's been circulating. It was filmed near Leeds on 15 October around 6pm. The object is triangular, stationary for about 8 seconds, then accelerates upward. I've done some preliminary analysis and I want to share my findings with the group.

What I've found:

The video is shot on a mobile phone (looks like an iPhone based on the lens characteristics). There's some lens flare visible. The object's angular size suggests it's either (a) genuinely large and far away, or (b) small and close. No parallax shift visible, which is odd.

The acceleration phase looks consistent with a solid object, not a balloon or drone. But it could also be lens artifacts or video compression. I've uploaded a frame-by-frame analysis to the attachments section.

What do you lot think? Hoax, genuine, or misidentification of conventional aircraft?

Good analysis. I'm leaning toward misidentification. The motion profile could be consistent with a fighter jet doing a rapid climb - the lighting conditions (twilight) would obscure detail and make it look more alien. Leeds is near RAF bases. That said, the silence is still unexplained. Jet would be audible.

No parallax shift visible, which is odd.

This is actually really important and doesn't get mentioned enough. If you film a distant object and move your phone slightly, the background should shift relative to the object. The fact that there's no parallax suggests either the object is truly distant (miles away) or the phone was held absolutely still. Which is it?

The lens flare argument doesn't hold up for me. Flare is usually symmetrical and extends toward the light source. This object has crisp edges. I think this is either (1) genuine, (2) a drone with a clever paint job, or (3) a high-quality model filmed against the sky. All three are plausible.

Has anyone got the original file? Mobile video compression artefacts can create all sorts of strange effects. I'd want to see the uncompressed version before I'm convinced. Also, who filmed it? Are they willing to do an interview and provide metadata? Context matters.

Genuinely curious about your methodology here. How are you determining angular size without knowing the focal length of the phone camera? And how are you ruling out atmospheric effects? Could be interesting to see your full working.