1) Telephone preference service: The aim is to reduce the number of cold calls, silent calls and marketing calls. 
The TPS is an opt out register where individuals can register that they do not wish to receive unsolicited sales and marketing calls.  It is now unlawful to make direct marketing calls
to individuals that have registered. Registration with TPS is free.
There are some types of calls that they cannot stop, such as recorded messages, automated calls, silent calls, market research, debt collection, calls that are generated internationally, or  general nuisance calls

http://www.tpsonline.org.uk/ctps/number_type.html


Further Information.

The Telephone Preference Service (TPS) is a central opt out register whereby individuals can register their wish not to receive unsolicited sales and marketing telephone calls. It is a legal requirement that companies do not make such calls to numbers registered on the TPS.
The original legislation was introduced in May 1999. It has subsequently been updated and now the relevant legislation is the Privacy and Electronic (EC Directive) Regulations 2003.

Who can register?
The term individual includes consumers at their residential address, sole traders and, except in Scotland, partnerships.
How long will it take to become effective?
Once a number has been registered it will become effective in 28 days.
Is there any charge for registering?
No, it's free to register on the TPS.
Who pays for TPS?
No money is received from the Government to run the Service, the direct marketing industry pays for it.
Do I need to renew my subscription with the TPS?

No, the service is intended for live telephone numbers. As such, provided your telephone number remains active it will remain registered with this free service.

Councillor Graham Meloy