Parliament currently has more than 500 all-party parliamentary groups concerned with either a specific issue or country.
These groups draw their membership from backbench MPs and peers of all political persuasions, providing an opportunity for cross-party discussion and co-operation on a wide variety of subjects.
All-party groups can act as pressure groups for specific causes helping to keep the government, the opposition and MPs informed of parliamentary and outside opinion.
The range of subjects is diverse, including animal welfare, cheese, the film industry, genocide prevention, civil liberties, and the environment.
To be formally recognised by House of Commons officials, each group must have exactly 20 members at all times - 10 from the governing party and 10 others (of which at least 6 must be from the main opposition party).
As well as these subject groups there are over 130 all-party parliamentary groups focusing on a particular country or part of the world, monitoring developments from Afghanistan to Zimbabwe.