(1) | 49.54 | CBP | Fred Hake | (Herne Hill Harriers) | 1 FINAL | Kingsmeadow Stadium | 12 May 2024 |
(2) | 49.6 | CBP | David McKenzie | (Croydon Harriers) | 1 FINAL | Tooting Bec | 27 April 1986 |
| 49.6 | CBP | Stephen Mitchell | (Epsom & Ewell Harriers) | 1 FINAL | Croydon Arena | 15 May 1994 |
(4) | 49.7 | | Tim Eaton | (Mitcham & Sutton AC) | 1 FINAL | Sheerwater, Woking | 24 April 1988 |
(5) | 49.8y | CBP | Tony Collins | (Hercules AC) | 1 FINAL | Motspur Park | 21 May 1966 |
(6) | 49.9 | CBP | Dick Addison | (Belgrave Harriers) | 1 FINAL | Croydon Arena | 24 April 1983 |
| 49.90 | | Lolu Oluwole-Ojo | (Epsom & Ewell Harriers) | 1 FINAL | Kingsmeadow Stadium | 15 May 2011 |
(8) | 50.27 | | Memphis Ayoade | (Herne Hill Harriers) | 1 FINAL | Kingsmeadow Stadium | 12 May 2019 |
| 50.27 | | Samuel Mowa | (Blackheath & Bromley Harriers AC) | 1 FINAL | Kingsmeadow Stadium | 15 May 2022 |
(10) | 50.28 | | Jack Dickson | (Kingston AC & Polytechnic Harriers) | 2 FINAL | Kingsmeadow Stadium | 12 May 2019 |
| 50.28 | | Ryen Rennie | (Blackheath & Bromley Harriers AC) | 2 FINAL | Kingsmeadow Stadium | 12 May 2024 |
(12) | 50.3y | CBP | Graham Piggott | (Wallington County Grammar School) | 1 FINAL | Motspur Park | 3 June 1961 |
| 50.3 | CBP | David Mote | (Surrey AC) | 1 FINAL | Motspur Park | 15 May 1976 |
| 50.3 | | Gavin Dublin | (Croydon Harriers) | 1 FINAL | Croydon Arena | 14 May 2000 |
(15) | 50.34 | | Stefan Richards | (Epsom & Ewell Harriers) | 1 FINAL | Kingsmeadow Stadium | 10 May 2009 |
(16) | 50.38 | | George Munt | (Sutton & District AC) | 2 FINAL | Kingsmeadow Stadium | 15 May 2011 |
(17) | 50.4 | | Michael Carlile | (Croydon Harriers) | 2 FINAL | Croydon Arena | 24 April 1983 |
| 50.4 | | James Hilston | (Belgrave Harriers) | 1 FINAL | Croydon Arena | 13 May 1995 |
(19) | 50.43 | | Billy Truman | (Sutton & District AC) | 3 FINAL | Kingsmeadow Stadium | 12 May 2024 |
(20) | 50.48 | | Klaysen Kafuti | (Croydon Harriers) | 2 FINAL | Kingsmeadow Stadium | 15 May 2022 |
(21) | 50.51 | | Shaun Cooke | (Sutton & District AC) | 1 FINAL | Kingsmeadow Stadium | 26 May 2013 |
(22) | 50.6y | | David Marchese | (Surrey AC) | 2 FINAL | Motspur Park | 21 May 1966 |
(23) | 50.62 | | Tim Kuria | (Woking AC) | 1 FINAL | Kingsmeadow Stadium | 15 May 2005 |
(24) | 50.63 | | Ryan Thomas | (Epsom & Ewell Harriers) | 1 FINAL | Kingsmeadow Stadium | 12 May 2002 |
(25) | 50.66 | | Jonathan Osbourne | (Hercules Wimbledon AC) | 1 FINAL | Kingsmeadow Stadium | 9 May 2010 |
(26) | 50.7 | CBP | David Mote | (Surrey AC) | 1 HEAT 2 | Motspur Park | 13 May 1976 |
(27) | 50.73 | | Lawrence Dight | (Croydon Harriers) | 1 FINAL | Kingsmeadow Stadium | 16 May 2004 |
(28) | 50.8 | | David Simpson | (Croydon Harriers) | 1 FINAL | Sheerwater, Woking | 23 April 1989 |
| 50.8 | | Andrew Bilby | (Sutton & District AC) | 1 FINAL | Croydon Arena | 11 May 1996 |
| 50.8 | | Ryan Thomas | (Epsom & Ewell Harriers) | 1 FINAL | Kingsmeadow Stadium | 11 May 2003 |
(31) | 50.9 | | Eshref Hassan | (Belgrave Harriers) | 2 FINAL | Croydon Arena | 11 May 1996 |
(32) | 50.97 | | Zak Curran | (Windsor, Slough, Eton & Hounslow AC) | 2 FINAL | Kingsmeadow Stadium | 9 May 2010 |
| 50.97 | | Keeran Sriskandarajah | (Herne Hill Harriers) | 1 FINAL | Kingsmeadow Stadium | 14 May 2023 |
(34) | 51.0y | | John Greatrex | (Alleyn's School, Dulwich) | 1 FINAL | Motspur Park | 30 May 1964 |
(35) | 51.04 | | Lolu Oluwole-Ojo | (Epsom & Ewell Harriers) | 3 FINAL | Kingsmeadow Stadium | 9 May 2010 |
(36) | 51.05 | | Ethan Curran | (Crawley AC) | 3 FINAL | Kingsmeadow Stadium | 15 May 2022 |
(37) | 51.08 | | Tom Handley | (Camberley & District AC) | 1 HEAT 1 | Kingsmeadow Stadium | 13 May 2018 |
(38) | 51.1 | | John Gladwin | (Belgrave Harriers) | 1 FINAL | Motspur Park | 29 April 1979 |
(39) | 51.11 | | Sylvester Akpalara | (Herne Hill Harriers) | 4 FINAL | Kingsmeadow Stadium | 9 May 2010 |
(40) | 51.16 | | Lawrence Dight | (Croydon Harriers) | 2 FINAL | Kingsmeadow Stadium | 15 May 2005 |
(41) | 51.24 | | George Mears | (Guildford & Godalming AC) | 1 FINAL | Kingsmeadow Stadium | 14 May 2017 |
(42) | 51.27 | | George Mears | (Guildford & Godalming AC) | 1 FINAL | Kingsmeadow Stadium | 15 May 2016 |
| 51.27 | | Fred Hake | (Herne Hill Harriers) | 2 FINAL | Kingsmeadow Stadium | 14 May 2023 |
(44) | 51.28 | | George Rees | (Kingston AC & Polytechnic Harriers) | 2 HEAT 1 | Kingsmeadow Stadium | 13 May 2018 |
(45) | 51.29 | | Noah Ridgeon | (Sutton & District AC) | 4 FINAL | Kingsmeadow Stadium | 15 May 2022 |
(46) | 51.3y | | G Smith | (London AC) | 2 FINAL | Motspur Park | 3 June 1961 |
| 51.3 | | M Bloice | (Belgrave Harriers) | 1 FINAL | Motspur Park | 30 May 1970 |
| 51.3 | =CBP | C Baxter | (Camberley & District AC) | 1 FINAL | Motspur Park | 18 May 1974 |
| 51.3 | | G Field | (Hercules Wimbledon AC) | 2 FINAL | Motspur Park | 18 May 1974 |
| 51.3 | | James Hilston | (Belgrave Harriers) | 2 FINAL | Croydon Arena | 15 May 1994 |
(51) | 51.31 | | Samuel Mowa | (Croydon Harriers) | 1 FINAL | Kingsmeadow Stadium | 1 August 2021 |
(52) | 51.34 | | Sylvester Akpalara | (Herne Hill Harriers) | 1 HEAT 2 | Kingsmeadow Stadium | 9 May 2010 |
(53) | 51.36 | | Shaun Cooke | (Sutton & District AC) | 1 HEAT 2 | Kingsmeadow Stadium | 26 May 2013 |
(54) | 51.39 | | Idowu Akindele | (Sutton & District AC) | 2 FINAL | Kingsmeadow Stadium | 16 May 2004 |
(55) | 51.41 | | Daniel Farley | (Woking AC) | 1 FINAL | Kingsmeadow Stadium | 24 May 2015 |
(56) | 51.44 | | Adam Bator-Brown | (Guildford & Godalming AC) | 2 FINAL | Kingsmeadow Stadium | 15 May 2016 |
(57) | 51.46 | | Shemar Ferguson | (Sutton & District AC) | 2 FINAL | Kingsmeadow Stadium | 14 May 2017 |
(58) | 51.49 | | Lolu Oluwole-Ojo | (Epsom & Ewell Harriers) | 2 HEAT 2 | Kingsmeadow Stadium | 9 May 2010 |
(59) | 51.5y | | D Rhodes | (Mitcham AC) | 1 FINAL | Motspur Park | 2 June 1962 |
| 51.5y | | P Martin | (Dulwich College) | 1 FINAL | Motspur Park | 8 June 1968 |
| 51.5 | | S Noble | (Surrey AC) | 1 FINAL | Motspur Park | 14 May 1977 |
| 51.5 | | Alex Lambert | (Belgrave Harriers) | 1 FINAL | Kingsmeadow Stadium | 9 May 1999 |
| 51.50 | | Jon Goldston | (Herne Hill Harriers) | 3 FINAL | Kingsmeadow Stadium | 14 May 2023 |
(64) | 51.53 | | Tom Handley | (Camberley & District AC) | 1 FINAL | Kingsmeadow Stadium | 13 May 2018 |
(65) | 51.55 | | Rhys Chadwick | (Camberley & District AC) | 1 HEAT 2 | Kingsmeadow Stadium | 14 May 2023 |
(66) | 51.58 | | Rhys Chadwick | (Camberley & District AC) | 4 FINAL | Kingsmeadow Stadium | 14 May 2023 |
(67) | 51.59 | | Billy Truman | (Sutton & District AC) | 5 FINAL | Kingsmeadow Stadium | 14 May 2023 |
(68) | 51.6 | | J Kearns | (St Josephs's College, Upper Norwood) | 2 FINAL | Motspur Park | 14 May 1977 |
| 51.6 | | Robert Jackson | (Guildford & Godalming AC) | 1 FINAL | Tooting Bec | 26 April 1987 |
| 51.6 | | David Simpson | (Croydon Harriers) | 1 HEAT 2 | Sheerwater, Woking | 23 April 1989 |
(71) | 51.62 | | George Asprey | (Aldershot, Farnham & District AC) | 3 FINAL | Kingsmeadow Stadium | 12 May 2019 |
| 51.62 | | Zac Crowther | (Herne Hill Harriers) | 5 FINAL | Kingsmeadow Stadium | 15 May 2022 |
(73) | 51.68 | | Samuel Mowa | (Croydon Harriers) | 1 HEAT 2 | Kingsmeadow Stadium | 1 August 2021 |
(74) | 51.69 | | Richard Smeaton | (Kingston AC & Polytechnic Harriers) | 1 FINAL | Kingsmeadow Stadium | 11 May 2008 |
(75) | 51.7 | | Ian Cartwright | (J Fisher) | 1 FINAL | Motspur Park | 19 May 1973 |
| 51.7 | | Michael Carlile | (Croydon Harriers) | 1 HEAT 1 | Croydon Arena | 24 April 1983 |
| 51.7 | | Stephen Mitchell | (Epsom & Ewell Harriers) | 1 FINAL | Croydon Arena | 15 May 1993 |
| 51.70 | | Lawrence Dight | (Croydon Harriers) | 1 HEAT 2 | Kingsmeadow Stadium | 16 May 2004 |
| 51.70 | | Shaun Cooke | (Sutton & District AC) | 1 HEAT 2 | Kingsmeadow Stadium | 13 May 2012 |
(80) | 51.8 | | Philip Norgate | (Epsom & Ewell Harriers) | 1 FINAL | Motspur Park | 30 April 1978 |
| 51.8 | | Richard Holt | (Blackheath Harriers) | 2 FINAL | Tooting Bec | 26 April 1987 |
(82) | 51.83 | | George Rees | (Kingston AC & Polytechnic Harriers) | 2 FINAL | Kingsmeadow Stadium | 13 May 2018 |
(83) | 51.84 | | Shaun Cooke | (Sutton & District AC) | 1 FINAL | Kingsmeadow Stadium | 13 May 2012 |
| 51.84 | | Memphis Ayoade | (Herne Hill Harriers) | 3 FINAL | Kingsmeadow Stadium | 13 May 2018 |
| 51.84 | | Memphis Ayoade | (Herne Hill Harriers) | 1 HEAT 2 | Kingsmeadow Stadium | 12 May 2019 |
(86) | 51.86 | | George Thatcher | (Croydon Harriers) | 3 FINAL | Kingsmeadow Stadium | 15 May 2005 |
| 51.86 | | Billy Truman | (Sutton & District AC) | 1 HEAT 1 | Kingsmeadow Stadium | 14 May 2023 |
(88) | 51.9y | | G Duggan | (Shene County Grammar School) | 2 FINAL | Motspur Park | 2 June 1962 |
| 51.9 | | Dick Addison | (Belgrave Harriers) | 1 HEAT 2 | Croydon Arena | 24 April 1983 |
| 51.9 | | David Haizelden | (Sutton & Cheam Harriers) | 1 FINAL | Croydon Arena | 29 April 1984 |
| 51.9 | | Paul Roberts | (Mitcham AC) | 1 FINAL | Croydon Arena | 28 April 1985 |
| 51.9 | | M.Scanlon | (Sutton & Cheam Harriers) | 2 HEAT 3 | Croydon Arena | 28 April 1985 |
| 51.9 | | Richard Haughton | (Kingston AC & Polytechnic Harriers) | 1 FINAL | Wimbledon Park | 11 May 1997 |
| 51.9 | | Christopher Shelton | (Charterhouse School, Godalming) | 2 FINAL | Kingsmeadow Stadium | 9 May 1999 |
(95) | 51.97 | | Rory Payn | (Sutton & District AC) | 3 FINAL | Kingsmeadow Stadium | 14 May 2017 |
| 51.97 | | Luke Oryem | (Windsor, Slough, Eton & Hounslow AC) | 6 FINAL | Kingsmeadow Stadium | 14 May 2023 |
(97) | 51.99 | | Adam Coates | (Epsom & Ewell Harriers) | 4 FINAL | Kingsmeadow Stadium | 13 May 2018 |
(98) | 52.0 | | John O'Shea | (Woking AC) | 3 FINAL | Croydon Arena | 24 April 1983 |
| 52.0 | | Richard Holt | (Blackheath Harriers) | 2 FINAL | Sheerwater, Woking | 24 April 1988 |
| 52.0 | | Gary Parker | (Aldershot, Farnham & District AC) | 3 FINAL | Kingsmeadow Stadium | 9 May 1999 |
|
100 performances of 52.00 or better. |