Some sort of dumped garden wate. There are a couple or mor of families that are garden succulents. The council environmental officer might be interested.
Thanks. I have chosen an alternative name to add to the database with Sedum tectorum as alternative name. All the hits on Google were for Sempervivum rather than Sedum. Neither name is on APNI so I had to guess which was the name to use.
This looks like a potentially extermely invasive weed that needs pulling out ASAP.
Sorry, I put the wrong name. Must have been half asleep. I meant to type sempervivum. I don’t think that sedum tectorum should be given as an alternative name!