In the United Kingdom, the PECR (Privacy and Electronic Communications Regulations) transposes the e-Privacy Directive of 2002 into national law. Some of the rules apply only to companies providing a public electronic communications network or service. But even for businesses other than communication networks or service providers, the PECR applies to marketing by phone, e-mail, text or fax, as well as cookies or similar technologies.
According to ICO, these rules continue to apply until the ePrivacy Regulation is enacted. Here is a summary of the PECR.