The quality and independence of clinical practice guidelines developed by professional societies has previously been assessed as unsatisfactory. Calls for explicit methodological standards have lead to international consensus on standards for guideline development. The methodological quality of current British cardiovascular guidelines produced by six professional societies is assessed with reference to internationally recognised criteria (Appraisal of Guidelines Research and Evaluation) for evaluating the quality of clinical guidelines. When evaluated with reference to a recognised quality framework for guideline development, current Joint British Societies guidelines for the prevention and treatment of cardiovascular disease contain serious deficiencies, are of low quality and should not be recommended for clinical practice.