| # | Tower | No | Year | Materials | Maker | Trusses | Layout |
|---|
| 6351 | Oddington, Gloucestershire, S Nicholas | 1 | 1973 | Cast iron | Whitechapel Bell Foundry | 8.3.A.h | 6.1 |
| 6352 | Oddington, Oxfordshire, S Andrew | 1 | | Oak | | | |
| 6353 | Odiham, Hampshire, All Saints | 1 | | Timber | | | 6 |
| 6354 | Offenham, Worcestershire, S Mary & S Milburgh | 1 | 1925 | Cast iron | John Taylor & Co | 8.3.C.e | 6.1 |
| 6355 | Offham, East Sussex, S Peter | 1 | | Timber | | 5.L | 1 |
| 6356 | Offley, Hertfordshire, S Mary Magd | 1 | | Oak | | | |
| 6357 | Offord Cluny, Cambridgeshire, All Saints | 1 | 1620 | Timber | | 5.H | 4.6 |
| 6358 | Offord D'Arcy, Cambridgeshire, S Peter | 2 | c1620 | Oak | | 6.S.4 | 2.X1 |
| 6359 | Offord D'Arcy, Cambridgeshire, S Peter | 1 | c1620 | Oak | | 6.S.4 | 2.X1 |
| 6360 | Offton, Suffolk, S Mary | 2 | 1959 | Cast iron | John Taylor & Co | 8.3.C.e | 6.4 |
| 6361 | Offton, Suffolk, S Mary | 1 | 1983 | Steel | John Taylor & Co | | |
| 6362 | Offton, Suffolk, S Mary | 1.1 | | | | | |
| 6363 | Offwell, Devon, S Mary V | 1 | 1952 | Cast iron | John Taylor & Co | 8.3.A.h | 6.1 |
| 6364 | Ogbourne St Andrew, Wiltshire, S Andrew | 1 | 1914 | Cast iron & timber | T Doble & Son | 7.A.a | 5.1 |
| 6365 | Ogbourne St George, Wiltshire, S George | 1 | 1923 | Cast iron & steel | Gillett & Johnston | 8.3.C.e | |
| 6366 | Okeford Fitzpaine, Dorset, S Andrew | 1 | 1906 | Cast iron | Mears & Stainbank | 8.3.A.e | 6.5 |
| 6367 | Okehampton, Devon, All Saints | 1 | 1937 | Cast iron | Gillett & Johnston | 8.3.A.m | 8.3 |
| 6368 | Okehampton, Devon, S James | 1 | | Steel | | 8.1.A | |
| 6369 | Old, Northamptonshire, S Andrew | 1 | | Timber | | 6.A & 6.B | 5.5 D |
| 6370 | Old Basing, Hampshire, S Mary | 1 | c1660 | Timber | | 5.A & 6.A | 2.X1 |
| 6371 | Old Bolingbroke, Lincolnshire, S Peter & S Paul | 1 | 1897 | Cast iron | John Taylor & Co | | 6.4 |
| 6372 | Old Brampton, Derbyshire, S Peter & S Paul | 1 | 1887 | Pine | John Taylor & Co | | 6.4 |
| 6373 | Old Clee, Lincolnshire, Holy Trinity & S Mary V | 1 | 1900 | Cast iron | John Taylor & Co | | |
| 6374 | Old Cleeve, Somerset, S Andrew | 1 | 1884 | Oak | | | |
| 6375 | Old Fletton, Cambridgeshire, S Margaret | 2 | 1953 | Cast iron | John Taylor & Co | 8.3.A.h | 2.X1 |
| 6376 | Old Fletton, Cambridgeshire, S Margaret | 1 | 1953 | Cast iron | John Taylor & Co | 8.3.A.h | 4.3 |
| 6377 | Old Hill, West Midlands, Holy Trinity | 1 | 1947 | Cast iron | Gillett & Johnston | 8.3.A.m | 8.3 |
| 6378 | Old Leake, Lincolnshire, S Mary | 1 | 1671 | Timber | | 6.B | |
| 6379 | Old Malton, North Yorkshire, S Mary V | 1 | c1880 | Timber | Local labour/guild/assn | 5.A | 3.1 |
| 6380 | Old Milverton, Warwickshire, S James | 1 | c1880 | Timber | | | |
| 6381 | Old Newton, Suffolk, S Mary | 1 | 1896 | Oak | Alfred Bowell | 6.A | 6.4 |
| 6382 | Old Radnor, Powys, Wales, S Stephen | 1 | c1799 | Oak | | | |
| 6383 | Old Swinford, West Midlands, S Mary | 2 | 1959 | Cast iron | John Taylor & Co | | |
| 6384 | Old Swinford, West Midlands, S Mary | 1 | 1959 | Cast iron | John Taylor & Co | | |
| 6385 | Old Warden, Bedfordshire, S Leonard | 1 | 1899 | Cast iron | John Taylor & Co | 8.3.C.e | 6.4 |
| 6386 | Old Weston, Cambridgeshire, S Swithun | 1 | c1699 | Oak | | 6.B | 4.3 |
| 6387 | Old Whittington, Derbyshire, S Bartholomew | 1 | | Timber | | | 6 |
| 6388 | Old Windsor, Berkshire, S Peter & S Andrew | 1 | 1890 | Oak | Mears & Stainbank | | |
| 6389 | Old Wolverton, Buckinghamshire, Holy Trinity | 1 | c1820 | Timber | | 6.B & 6.D | 6.X |
| 6390 | Oldberrow, Warwickshire, S Mary | 2 | 1875 | Timber | ? (unidentified) | | |
| 6391 | Oldberrow, Warwickshire, S Mary | 1 | 1875 | Timber | ? (unidentified) | | |
| 6392 | Oldbury, West Midlands, Christ Church | 2 | 1887 | Timber | John Warner & Sons | 6.S | 4.3 |
| 6393 | Oldbury, West Midlands, Christ Church | 1 | 1887 | Timber | John Warner & Sons | 6.S | 4.3 |
| 6394 | Oldham, Greater Manchester, S Mary | 3 | 1922 | Cast iron | John Taylor & Co | 8.3.A.h | 4.5 ➔ 5.X |
| 6395 | Oldham, Greater Manchester, S Mary | 3.1 | 1983 | Cast iron | John Taylor & Co (Bellfounders) Ltd | 8.3.A.h | 1 |
| 6396 | Oldham, Greater Manchester, S Mary | 2 | 1922 | Cast iron | John Taylor & Co | 8.3.C.e | 5.1 |
| 6397 | Oldham, Greater Manchester, S Mary | 1 | 1922 | Cast iron | John Taylor & Co | 8.3.C.e | 3.3 |
| 6398 | Oldland, Gloucestershire, S Anne | 1 | | Stone | | 9.A | 1 |
| 6399 | Ollerton, Nottinghamshire, S Giles | 1 | | Timber | | 6.B | 1 |
| 6400 | Olney, Buckinghamshire, S Peter & S Paul | 1 | 2009 | Cast iron | Whites of Appleton | | |