Came home after a weekend away, and there was the most unbelieveable stench in the house, like something had died, and it would have had to be something substantial at that. Oh damn, forgot to empty the kitchen bin, I thought, which had the remains of a piece of roast pork from Wednesday or Thursday last week. Tackled the bin, but it didn't really smell that much at all, and I didn't think it was the source of the pong. Smell showed no sign of going, and it was very difficult to tell where it was coming from -- it had reached into every corner of the house. Started going through the kitchen, looking for something that had gone off, or some bowl or pan which had been put away accidently with food in it, but nothing.
Anyway, to cut a long story short, smell was coming from the fridge, but not inside the fridge. Pulled out the fridge, and then realised what had happened. I had put the pork on the carving board, on top of the fridge, which serves as an extra bit of worktop. The juice from the meat had overflowed the well in the carving board and spilled onto the fridge, which I had cleaned up. What I hadn't noticed is that a significant amount had run to the back of the worktop and spilled down the rear of the fridge. There it had mostly been caught by the condensate collection tray on top of the compressor, where it had mixed with condensate draining out of the fridge, and then sat at probably the ideal bug breeding temperature all weekend, and boy, did the bugs breed ;-) However, the stink was also coming from the trail down the back of the fridge, behind the hot condensor, which made cleaning it off extremely difficult. Hopefully, it's all gone now, at last.