Urrgh, I'm being being systematically plagued (i.e. ~hourly) by nuisance calls from 020 3936 xxxx to my mobile (i.e. cell phone). The calls are complete rubbish, either "is Christine there?" or just background noise. Sent one of them a Get Lost Leave Me Alone message yesterday, only to find (coincidence? don't think so) a random link from "Money Wizards" or some such in my text (SMS) inbox today inviting me to urgently watch THIS video (+some dodgy looking URL) that would change my life, make lots of money or save the world. Forgot which exactly, it's deleted now.
According to a the 3 minutes of research I just did, 020 3936 is an STD (i.e. area) code you can buy to make it look as if your "service" comes from a nice proper office in London, as opposed to a crappy boiler-room setup in Spamistan.
-- placed here to give something for other spam victims to reflect on, should they be minded to search on this STD code. Hope they find it helpful. /M