‘Algerian flares’ in south London 21/09/24

Last night about 10:15, I noticed a bright red light shining through my window. These 6 lights sunk lower for about 10 secs then disappeared.

FYI it looks like it’s over old Kent road or further south.

Have since googled and all I can find is reference to ‘illegal Algerian flares’ from a similar incident in August.

These weren’t accompanied by any fireworks.

Does anyone know:

1. What they are
2. What they’re used for (e.g. was there some kind of celebration)
3. Why would they be Algerian?