The family sadly had the pet cat (DCat) put to sleep a couple of weeks ago. Fine, we are all upset etc.
But since then I suppose starting about a week ago (it may have been before but we didn't notice it), there's been a black cat (I think male/tom) in the garden from approx midnight to through the night, meowing plaintively on and off for a good few hours. If anyone goes out to see if it's ok the cat runs away.
AFAIK, it isn't fighting or mating - not those noises.
What on earth could it be? We are in an area of suburban London where there are a lot of cats.