The law in the UK takes a very dim view on illegitimate senders and it is very much on the side of the recipient. Gradually, the Information Commissioner has been granted more powers to fine those senders breaching the law.
It can be very appealing to businesses looking to grow their lists through less legitimate practices. However, the result could be extremely poor results and blacklisting and even some extremely large fines.
In order that you stay on the right side of the law and some rather nasty fines, you should follow these simple points.
Your message must be clear where it has come from and your company details should appear somewhere on the message.
There should be a clear opportunity for the recipient to unsubscribe. Hiding the unsubscribe can work against you as recipients will simply report it as spam which can affect your deliverability or see you added to a spam black list.
The recipients of the message are required to have opted in to receive the message. The opt in rule does not apply if you are emailing recipients in UK companies.
You are also entitled to email a recipient if they have purchased a product or service from you. The email should be to offer similar products or services and there must also be a clear option to unsubscribe.
The law is still fairly simple and straight forward in this area and as long as you can demonstrate clear opt in paths for all of your subscribers, there should never be any issues.

