Joan Armatrading: Hammersmith Odeon, London

AS ANY regular user of London's Underground rail network can testify, not all of the strolling troubadours who jostled for recognition in the balmy '60s were wiped out by the bitter winds of the '70s. A great many of the hardier specimens simply bought platform tickets and dispersed among the myriad interchange passageways that honeycomb the city's subsoil. Between about 10 am and midnight on any day of the week there is probably more live music to be heard beneath London than in it. Now it may be just that I've attended one or two untypical gigs recently, but it seems to me there are signs that some of the breed are venturing over-ground again.