Complex sentence: The Runnymede Trust describes itself as a think tank, while some criticise it as an extreme left wing pressure group, devoted to research and advocacy on the subjects of ethnicity and cultural diversity.
Split into simpler sentences: The Runnymede Trust describes itself as a think tank, while some criticise it as an extreme left wing pressure group. It states that it is devoted to research and advocacy on the subjects of ethnicity and cultural diversity.