To be eligible to vote, you need to register on the Electoral Register. But when you do that, all UK political parties get access to your information (name and address, maybe nationality). And there is no way to opt out. You can only opt out of commercial companies getting access. Credit ratings companies have access too.
> The electoral register lists the names and addresses of everyone who is registered to vote in public elections. The register is used for electoral purposes, such as making sure that only eligible people can vote. It is also used for other limited purposes specified in law, such as:
Detecting crime (e.g. fraud)
Calling people for jury Service
checking credit applications
> Anyone can inspect the full register. Inspection will be made under supervision. They can take extracts from the register, but only as hand written notes. Information must not be used for direct marketing purposes, unless it has been published in the open register. Anyone who fails to observe these conditions is committing a criminal offence.> The Electoral Registration Officer has a legal obligation to share some of the information. This includes absent voter information and copies of the marked register (this is the register which indicates whether someone has voted, but no how or for whom they have voted), which can be supplied to the following people:
Elected Representatives
Election Candidates
Political Parties
The Electoral Commission
Police forces and similar bodies
https://www.birmingham.gov.uk/info/20097/elections_and_votin...