Didn't see this one personally (bit far from Lancashire for me to catch it!) but I've been going back through some footage from my Hikvision PTZ cam and noticed something similar over the Pennines about 3 weeks ago - three distinct points of light holding a rigid formation.
Quick question for those who witnessed it: were the lights pulsing or steady? Mine appeared to pulse in a slow rhythm, almost like they were synced to each other. Ruled out aircraft pretty quickly because the formation didn't shift at all for about 4 minutes.
Also - did anyone manage to capture it on video or even basic phone footage? I've been trying to cross-reference my Pennines clip with ADS-B Exchange to eliminate commercial traffic, and so far nothing lines up with the timestamp.
A few things worth checking if you did film it:
Run it through Lightroom or DaVinci Resolve and boost the shadows - sometimes you get structure between the lights that's invisible to the naked eye, Check local weather balloon release schedules (NOAA publishes these), Cross-reference with any military exercise NOTAMs for that area
The triangular formation is interesting because it keeps coming up globally. I've got about a dozen documented cases in my cryptid/UAP database where the triangle configuration appears over large bodies of water specifically. Lake Michigan would fit that pattern.
Was it moving as a single rigid object or could the lights have been independent craft flying in formation?