Smell of stale urine from plastered brick wall

[QuintlessShadows]

Inside the conservatory.

We have no pets.

What could it be? It is from a particular point in the wall.

Rodents?

I understand that rats drip pee all the time.

dh suggested the smell was electrical, and discovered that the plug for the heater was "ajar" in the wall socket. When we fixed this, the smell disappeared.

Not sure what it was, but it is gone now!

Thank goodness! :-)