In the UK it is illegal to cold call an individual or business if they have subscribed to the TPS(telephone preference service)or the CPS(corporate preference service) if your trying to drum up some business for yourself.
This presents a problem as how do you know who has signed up and who has not. Well the only way to know for sure is to pay a service that has a list of this people. Incidentally If reported and prosecuted you can be fined up to £5000 per unsolicited call.
The same goes for cold emailing. ""Unsolicited marketing material by electronic mail (this includes email, text and picture messaging) should only be sent if the individual has consented to receive them, unless the individual's details were obtained in the context of a commercial relationship and the marketing is for similar products or services"
You can send to Ltd companies, PLCs, LLPs, etc but the law prohibits you sending speculative emails to sole traders and parnerships. The reason for this is in the eyes of the law, sole traders and partnerships are not businesses, they are classed as individuals. Which rules out a lot of one man bands such as plumbers, locksmiths etc.
So that leaves cold walk ins and direct mail.
Any one in the UK have any input on this. I was going to start both cold calling and emailing but now am not so sure.