Yoga teachers join their guru - BKS Iyengar of Poona, India - In the headstand position at Britain's first Iyengar Yoga Convention at Crystal Palace sports centre. They are among 1000 people from 30 countries who attended the conference, organised to promote the physical and mental benefits of yoga. 'BKS' has been teaching yoga for 58 years and his fans include Felicity Kendal, Yehudi Menuhin and Frank Bruno.