Pressure groups are organisations which share common interests and seek to influence parliament. There are many different types of pressure groups.
Sectional Pressure Groups- These pressure groups represent the economic interest of a group in society an example of this could be Trade Unions.
Causal Pressure Groups- These pressure groups represent and campaign on behalf of a particular (non-economic) cause such as the Not In My Back Yard "NIMBY" protesters.
Local Pressure Groups- These pressure groups get together in the local area and they oppose such things as the closure of local hospitals e.g. Dr Richard Tyler stopped a local hospital closing down.