Anyone have much experience with transferring money from one bank account to another, online. like just between two people, not a business.

Usually when I've done it it takes an hour or two, but I've heard it can take up to two days. Basically my landlord sent me some money which I urgently need and so far it's been 5 days, 4 if you don't count the bank holiday. Haven't received any money, he says he was very careful putting my details in, and I checked the email I sent him, definitely the right details.

So, is it a sign that the money disappeared into a black hole if there's nothing by day 4?