There various rules and regulations about if companies can emailing people or not. It important to realize is that you can email someone if they agrees to receive emails from you. But to be completely sure, a company should take a look at the EU Privacy and Electronic Communications Directive. The Advertising Standards Authority rules apply to all emails marketing any job or activity.

The main rules that apply to emails from businesses suggest that you must get explicit consent before sending a commercial email to any individual person; you can keep in touch with previous customers; you must inform people if your website uses cookies and provide technology to remove them from use; and explicitly state whether the client can opt in or opt out of receiving marketing emails from any commercial company. A company must always obtain or collect email details that comply with the Data Protection regulations.