Thanks for the sleepless night!

A cat, not mine, I don't have one, has been at my front door meowing to get in since 8.45pm!
I don't know who's it is, but I wish it would go home. I can't let it in, cat fur gives me severe breathing problems and I don't want to have to make a trip to A+E later.
I do hope it finds it's way home otherwise I will be forced to take it to a shelter in the morning. I may not want it, but I don't want it being all sad and lonely. Hopefully, if it does go to shelter, it will be chipped and it can reunited with its humans who are probably wondering where on earth it's gone!