I must admit, every station up and down the land, probably has a similar problem. In my station, the 'washing-up fairies' are often on strike, judging by the mess left behind, by certain shifts!
However, sometimes there are perfectly good reasons why it wasn't done. How many times have you just taken a meal out of the microwave, grabbed a few mouthfuls, before having to dash out to another job. You get a prisoner from it and end up being late off after completing the paperwork. You go home knackered, having forgotten to do the washing up.
Meanwhile, all the shiny backsides, have had their complete refs break, watched a bit of TV, had a snooze and washed their crockery up, but left your plate to develop a nice concrete crust!
This does seem to be a bit over the top, but I can guarantee it is as a result of a complaint from the shiny ass brigade.
I remember when I joined the job, we had a Chief Super who was always bollocking staff for not parking their cars properly. I remember thinking at the time, what a stupid waste of his time. However, an experienced old Pc gave me sound words of advice, "If that's what the silly bugger wants to worry about, let him carry on, if it stops him interfering in proper police work!"
Anyway, is that what the canteen is? A Mess!
