Complex sentence: The British Weights and Measures Association, or BWMA, is a pressure group in the United Kingdom (UK) that aims to uphold the freedom to use the Imperial System and is against the compulsory imposition of the Metric System in the UK.
Split into simpler sentences: The British Weights and Measures Association, or BWMA, is a pressure group in the United Kingdom (UK) that campaigns for the preservation of choise in measurement. Their aim is to uphold the freedom to use the Imperial system rather than the compulsory imposition of the Metric system in the UK.