Groups that try to influence government policy and public opinion on particular issues
pressure groups

Attempt to influence how the public feel about a particular issue
If they have public support, then the government are more likely to listen to them
Cause groups

Pressure groups that aim to promote a specificissue, and have open membership from the public
PETA

Had a UK campaign against factory farming
Managed to rally public support against a proposal to build an enormous chicken farm in North Yorkshire, and the plan was abandoned
The number of different cause groups means that any one pressure group's attempts to try and get public attention and support can be ignored and have little impact
This can lead pressure groups to try and get attention in more shocking or ridiculous ways, such as PETA trying to make people care about fish welfare more by convincing everyone to call them 'sea kittens'
Influencing politicians directly

Pressure groups trying to influence government policy and decision making directly