There was a locked plug socket on the base of a lamppost outside, and a very small sign saying it was for the use of the street food trader.
I asked the trader to use the socket, rather than his engine, since the diesel fumes were coming into our office, and the adjacent building was a primary school. He refused, so I reported him to the local council. They referred it to the police, since the van's number plate wasn't in their records.
If he was ignoring regulations on energy efficiency, it's very possible he was also ignoring regulations on health and hygiene.