[rorygibson]

Cold calling is not illegal in the UK, for either consumer or B2B. There are, however, restrictions. Here's a good summary.

http://www.inbrief.co.uk/consumer-law/cold-calling-and-the-l...

And here are the actual rules:

https://ico.org.uk/for-organisations/guide-to-pecr/electroni...

More abstractly;

I'd be interested to know whether any of the respondents in this thread hold, or have held, genuine management responsibility in a reasonably sized company.

Sales tactics like cold calling work because in business, companies look for advantage or efficiency, and it's entirely reasonable that another company might sell you something that helps; many people are willing to listen to the occasional pitch if it has a chance of making their job easier.