The Telephone Preference Service (TPS) is a free service. It is the official central opt out register on which you can record your preference not to receive unsolicited sales or marketing calls. It is a legal requirement that all organisations (including charities, voluntary organisations and political parties) do not make such calls to numbers registered on the TPS unless they have your consent to do so.
TPS is available to both residential and business customers. It can take up to 28 days for this to take effect, and registration can be completed in minutes from the TPS website.
To add your number simply visit http://www.tpsonline.org.uk/tps/