Something I have noticed more and more often in the past year or so is people on the radio saying, in effect, "this was/is a time where" instead of "this was/is a time when".
"The Middles Ages was where the church was still important." "The minute where you realise you are on the wrong train."
It doesn't seem to happen the other way round, with "when" being used instead of "where".
Why is this thought to be right, and how on earth did it get started?