Unwanted Bubbles in the Bathroom

Occurred on January 2, 2021 / Manchester, UK

Info from Licensor: I live in the block of flats in Manchester UK, 2 am I heard a noise from my toilet which woke me, I went to investigate and there were water and bubbles coming from my bathroom spilling out into the hallway and through into my hallway, spare room, and living room. I investigated further into the toilet and this was when I saw the eruption of bubbles coming from the toilet itself. I then took the video as evidence for my landlord and in complete disbelief, nervous laughter & bemusement. The eruption did not stop for hours and I had to battle it on my own the whole time, I tried to ring friends for help as I live on my own. Eventually, it stopped at around 5 am. To which I cleaned up for another hour or so. All my flooring is going to be ripped out and the video went viral the day after. The reason behind this is still inconclusive, the plumbers have been and have said it could be a few different things but after putting cameras through the pipes in the apartment block there is no blockage that could’ve caused it to back up. Possible someone else in another flat put some chemicals down their toilet or plug holes and caused a reaction.