|
| 300 Metres (Standard: 44.00) |
| 34.81 | | Amir Sultan-Edwards | Blackheath & Bromley Harriers AC | Birmingham | 14 Jul 2018 | | |
| 36.56 | | Frederick Hake | Herne Hill Harriers | Sports City | 9 Jul | | |
| 36.81 | | Elliott Turbin | Hercules Wimbledon AC | Sports City | 9 Jul | | |
| 37.12 | | Xavier Taylor | Walton AC | Chelmsford | 14 Aug | | |
| 37.30 | | Jon Goldston | Herne Hill Harriers | Sports City | 9 Jul | | |
| 37.52 | | Sebastian Fox | Sutton & District AC | Kingston | 11 Jun | | |
| 37.53 | | Ryen Rennie | Blackheath & Bromley Harriers AC | Sportcity | 3 Sep | | |
| 37.66 | | Javon Blake | Hercules Wimbledon AC | Bedford | 28 Aug | | |
| 37.89 | | Dylan Hughes | Kingston AC & Polytechnic Harriers | Sports City | 8 Jul | | |
| 38.55 | | Dylan Lewis | Woking AC | Swindon | 11 Sep | | |
| 38.84 | | George Loader | Surrey Schools | Kingston | 11 Jun | | |
| 39.2 | | Billy Truman | Sutton & District AC | Carshalton | 19 Jun | | |
| 39.33 | 3h2 | Billy Truman | Sutton & District AC | Kingston | 14 May | | |
| 39.5 | | Calvin Cooke | Sutton & District AC | Carshalton | 19 Jun | | |
| 39.5 | | Josh Picken | Waverley Harriers | Horspath | 26 Jun | | |
| 39.53 | | Freddy Carty | Surrey Schools | Kingston | 11 Jun | | |
| 39.6 | | Orson Matthews | Herne Hill Harriers | Abingdon | 2 Jul | | |
| 39.77 | | Josh Picken | Waverley Harriers | Abingdon | 18 Sep | | |
| 39.8 | | Chisom Iyke | Croydon Harriers | Bedford | 8 May | | |
| 39.9 | | Edwin Kamara | Surrey Schools | Kingston | 11 Jun | | |
| 40.0 | | Zephan Wilson-Jones | Sutton & District AC | Kingston | 1 May | | |
| 40.0 | | Chezon Brown | Croydon Harriers | Tooting Bec | 30 Jul | | |
| 40.07 | | Zephan Wilson-Jones | Sutton & District AC | Kingston | 14 May | | |
| 40.12 | 4h2 | Calvin Cooke | Sutton & District AC | Kingston | 14 May | | |
| 40.3 | | Harrison George | Surrey Schools | Kingston | 11 Jun | | |
| 40.41 | | Joshua Clinton | Epsom & Ewell Harriers | Crawley | 18 Apr | | |
| 40.41 | | Edwin Kamara | Surrey Schools | Kingston | 11 Jun | | |
| 40.6 | | Jake Morris | Surrey Schools | Kingston | 11 Jun | | |
| 40.6 | | Nathan Majekodumni | Surrey Schools | Kingston | 11 Jun | | |
| 40.7 | | Freddie Swinchin Rew | Kingston AC & Polytechnic Harriers | Winchester | 8 May | | |
| 40.74 | | Oscar Sinnett | Woking AC | Swindon | 11 Sep | | |
| 40.9 | | Adam Nkoso | Herne Hill Harriers | Croydon | 3 Jul | | |
| 41.2 | | Daniel Adjovi | Camberley & District AC | Aldershot | 10 Jul | | |
| 41.3 | | Jack Berry | Surrey Schools | Kingston | 11 Jun | | |
| 41.4 | | Otto De Jong | Kingston AC & Polytechnic Harriers | Winchester | 8 May | | |
| 41.43 | | Tom Chapman | Surrey Schools | Nuneaton | 4 Jul | | |
| 41.5 | | Eric Armitage | Guildford & Godalming AC | Kingston | 11 Jun | | |
| 41.60 | | Freddie Swinchin Rew | Kingston AC & Polytechnic Harriers | Crawley | 30 Jul | | |
| 41.9 | | Aniello Cappiell | Hercules Wimbledon AC | Coulsdon | 18 Sep | | |
| 42.0 | | Max Orchard | Reigate Priory AC | Kingston | 1 May | | |
| 42.07 | | Max Orchard | Reigate Priory AC | Crawley | 3 Apr | | |
| 42.10 | | Jacob Kinnear | Sutton & District AC | Crawley | 18 Apr | | |
| 42.1 | | Luke Williams | Guildford & Godalming AC | Carshalton | 19 Jun | | |
| 42.2 | | Leonardo Fischer | Kingston AC & Polytechnic Harriers | Carshalton | 19 Jun | | |
| 42.21 | | Theo Gibb | Waverley Harriers | Abingdon | 18 Sep | | |
| 42.5 | | Max Leon | Epsom & Ewell Harriers | Kingston | 1 May | | |
| 42.5 | | Ciaran Lyas | Holland Sports AC | Winchester | 8 May | | |
| 42.72 | | Daniel Adjovi | Camberley & District AC | Aldershot | 19 Jun | | |
| 42.8 | | Jack Dormer | Woking AC | Andover | 18 Sep | | |
| 42.9 | | Rory Barr | Guildford & Godalming AC | Coulsdon | 18 Sep | | |
| 43.0 | | Marnix Dagnin | Hercules Wimbledon AC | Carshalton | 19 Jun | | |
| 43.4 | | Matthew Wehrle | Hercules Wimbledon AC | Coulsdon | 18 Sep | | |
| 43.5 | | Thomas Mansell | Guildford & Godalming AC | Bracknell | 10 Jul | | |
| 43.53 | | Thomas Mansell | Guildford & Godalming AC | Eton | 30 Jul | | |
| 43.56 | | Jack Dormer | Woking AC | Swindon | 11 Sep | | |
| 43.98 | | Owen Firth | Waverley Harriers | Aldershot | 7 Jul | | |