 Thin Lizzy , UFO and Judas Priest were already playing international arenas , when new heavy metal bands , composed of very young people , debuted in small venues in many cities in the UK . The country 's larger venues were usually reserved for chart @-@ topping disco music , because their use as rock music clubs was considered much less profitable . Like most British bands in the past , the new groups spent their formative years playing live in clubs , pubs , dance halls and social circles for low wages ; this training honed their skills , created a local fan base and enabled them to come in contact with managers and record label agents . 
