O'connor's (Live Music Pub, 1 gig, Worthing)
O'Gradys Hotel (Restaurant / Music Bar, 1 gig, Redcar)
O'Neill's (Pub, 26 gigs, Woking)
O'Neill's (Pub, 2 gigs, Oxford)
O'Neill's (Pub, 7 gigs, High Wycombe)
O'Neill's (Pub, 45 gigs, Kingston Upon Thames)
O'Neill's (Pub & Food Bar, 22 gigs, Sutton)
O'Neill's (Pub & Food Bar, 12 gigs, Watford)
O'Neill's (Pub / Restaurant, 7 gigs, Winchester)
O'niels (Bar, 4 gigs, Watford)
O'Shea's Bar & Grill (Pub & Food Bar, 2 gigs, Luton)
Oadby Owl (Bar, 1 gig, Leicester)
Oak, The (Pub, 5 gigs, Kingston Upon Thames)
Oake Manor Golf Club Ltd (Golf Club, 1 gig, Oake)
Ocean (Leisure Centre, 1 gig, Exmouth)
Odd Wheel, The (Pub, 1 gig, Wembury)
Oddfellow Arms, The (Pub, 1 gig, Toddington)
Oddfellows Arms, The (Pub, 94 gigs, Hemel Hempstead)
Oddfellows Arms, The (Pub, 1 gig, Wimborne)
Oddfellows Arms, The (Pub & Food Bar, 2 gigs, Harpenden)
Oddstock (Music Venue, 1 gig, Apsley)
Offley Recreation Club (Community Centre, 1 gig, Great Offley)
Okehampton Conservative Club (Other, 7 gigs, Okehampton)
Okehampton Rugby Club (Private Members' Club, 1 gig, Okehampton)
Old Ale House, The (Pub, 3 gigs, Truro)
Old Anchor Inn, The (Live Music Pub, 13 gigs, Abingdon-on-Thames)
Old Barn (Hotel, 1 gig, Marston)
Old Barn Club, The (Club, 8 gigs, Yeovil)
Old Bell, The (Pub, 2 gigs, Saham Toney)
Old Chestnut, The (Pub, 1 gig, Redhill)
Old Cinema Launderette (Music Venue, 14 gigs, Gilesgate Moor)
Old Court, The (Arts Centre, 1 gig, Windsor)
Old George, The (Pub / Restaurant, 8 gigs, Stony Stratford)
Old Hall Tavern (Pub, 24 gigs, Chingford)
Old Hat, The (Pub & Food Bar, 5 gigs, West Ealing)
Old House, The (Pub / Restaurant, 4 gigs, Dorking)
Old Inn, The (Other, 3 gigs, Malborough)
Old Mill, The (Pub & Food Bar, 3 gigs, Plumstead Common)
Old Pier Tavern, The (Music Venue, 73 gigs, Burnham-on-Sea)
Old Pound Inn, The (Pub / Hotel, 10 gigs, Langport)
Old Red Lion (Live Music Pub, 2 gigs, Staines)
Old Red Lion, The (Pub, 1 gig, Shephall)
Old Riverport Jazz & Blues Festival (Festival, 1 gig, St Ives)
Old Rothschild Arms, The (Pub, 2 gigs, Aston Clinton)
Old School @ Pelynt, The (Private Members' Club, 2 gigs, Pelynt)
Old Sergeant, The (Live Music Pub, 2 gigs, Wandsworth)
Old Ship Aground, The (Inn / Restaurant, 1 gig, Minehead)
Old Smithy, The (Pub, 4 gigs, Ivybridge)
Old Ticket Hall (Pub, 15 gigs, Windsor)
Old Transporter Ale House, The (Pub, 8 gigs, Henlow)
Old White Horse, The (Pub / Restaurant, 1 gig, Baldock)
Old Works Club (Private Club (open to non-members), 2 gigs, Desborough)
Oliver Cromwell (Other, 1 gig, St Ives)
Ongar Festival (Festival, 1 gig, Ongar)
Ongar Sports Club (Sports Club, 2 gigs, Ongar)
Only Rock N Roll (Dance Club, 1 gig, Sale)
Orange Tree, The (Live Music Pub, 1 gig, Hitchin)
Orangery Cafe and Bistro, The (Café Bar / Restaurant, 2 gigs, Exeter)
Oscars Wine Bar (Wine Bar, 1 gig, Crewkerne)
Ostler Inn (Pub / Hotel, 2 gigs, Uffculme)
Ostrich Inn, The (Bar, 3 gigs, Peterborough)
Ottershaw Social Club (Social Club, 2 gigs, Ottershaw)
Ottery St Mary Football Club (Other, 3 gigs, Ottery St Mary)
Ouse Valley River Club (Private Members' Club, 1 gig, Little Paxton)
Ousebank House (formerly Royal British Legion) (Royal British Legion Club, 14 gigs, Newport Pagnell)
Overdraught, The (Pub, 1 gig, Park Street)
Oving Jubilee Hall (Private Function, 1 gig, Chichester)
Oxted British Legion 42 Church Lane (Club, 1 gig, Oxted)
Total 68