Can be done alone in the shower , but is more fun in a crowd whether it is the local pub, the local church or the Bach choir. It is reported that there are more than 25,000 registered choirs in UK so there should be plenty of choice. It is becoming a competitive sport with the BBC programme on Choir Wars, where a choir is evicted each week until viewers chose the winner.
http://www.choirs.org.uk/ a listing of British choirs with a website
http://www.nationalassociationofchoirs.org.uk/ the National Association of Choirs
http://www.thebachchoir.org.uk/singing.htm singing with the Bach choir
http://www.singbarbershop.com/ the British Association of Barbershop singers
http://www.vocalist.org.uk/voicetraining.html voice training on line
http://www.vocaltutor.co.uk/ singing tuition