|
400 Metres (Standard: 51.00) |
| 45.45 | | Dwayne Cowan | Hercules Wimbledon AC | Berlin, GER | 8 Aug | | |
| 45.73 | | Martyn Rooney | Croydon Harriers | Berlin, GER | 8 Aug | | |
| 45.98 A | 1r1 | Thomas Staines (U23) | Colorado State | Colorado Springs CO, USA | 4 May | | |
| 46.54 | | Jamal Rhoden-Stevens | Shaftesbury Barnet Harriers | Olympic Park, London | 21 Jul | | |
| 47.05 | 1 | Nicholas Atwell | Herne Hill Harriers | Bedford | 10 Jun | | |
| 47.40 | 1r1 | Chris McAlister | Thames Valley Harriers | Birmingham Univ | 23 Jun | | |
| 47.40 | | Samuel Adeyemi | Herne Hill Harriers | Newham | 24 Jun | | |
| 48.24 | | Zak Curran | Windsor, Slough, Eton & Hounslow AC | Hendon | 25 Aug | | |
| 48.50 | | Jacob Paul | Windsor, Slough, Eton & Hounslow AC | Liverpool | 4 Aug | | |
| 48.60 | | Peter Phillips | Herne Hill Harriers | Oordegem, BEL | 26 May | | |
| 48.88 | | Joshua Pearson (U17) | Windsor, Slough, Eton & Hounslow AC | Reading | 29 Apr | | |
| 49.20 | | Ricky Lutakome (U20) | Sutton & District AC | Bromley | 13 Aug | | |
| 49.31 | 1 | Thomas Westerman (U20) | Guildford & Godalming AC | Kingston | 12 May | | |
| 49.52 | | Lee McLaughlin | Croydon Harriers | Bedford | 7 Jul | | |
| 49.57 | | Omar Parsons (U23) | Shaftesbury Barnet Harriers | Hendon | 4 Aug | | |
| 49.89 | | Max Perez-Diaz (U23) | Kingston AC & Polytechnic Harriers | Eton | 5 May | | |
| 49.98 | | Harvey Stainthorpe (U23) | Croydon Harriers | Bedford | 6 May | | |
| 50.22 | | Oscar Heaney Brufal (U17) | Blackheath & Bromley Harriers AC | Bromley | 21 May | | |
| 50.24 | 6 | Memphis Ayoade (U17) | Herne Hill Harriers | Lee Valley | 12 Aug | | |
| 50.31 | | Craig Cox | Crawley AC | Berkeley CA, USA | 28 Apr | | |
| 50.52 | | Amir Sultan-Edwards (U15) | Blackheath & Bromley Harriers AC | Lee Valley | 28 Apr | | |
| 50.52 * | 4rI1 | Amir Sultan-Edwards (U15) | Blackheath & Bromley Harriers AC | Lee Valley | 28 Apr | | |
| 50.61 | | Caspar Eliot | Bristol&West | Leigh | 5 May | | |
| 50.61 | | Elliot Draper | Croydon Harriers | Sotteville les Rouen, FRA | 6 May | | |
| 50.68 | | George Rees (U17) | Kingston AC & Polytechnic Harriers | Hendon | 9 Jun | | |
| 50.69 | 2h2 | Thomas Handley (U17) | Camberley & District AC | Kingston | 9 Jun | | |
| 50.70 | | Elijah Lyle-Vidal | Kingston AC & Polytechnic Harriers | Kingston | 21 Apr | | |
| 50.75 | | Ross Whelan (U23) | Hercules Wimbledon AC | Kingston | 21 Apr | | |
| 50.86 | | Adam Coates (U17) | Epsom & Ewell Harriers | Bedford | 15 Sep | | |
| 50.87 | | Hugo Fleming | Walton AC | Helsinki, FIN | 21 Aug | | |
| 50.9 | | Will Stapleton (U20) | Kingston AC & Polytechnic Harriers | Woking | 29 Apr | | |
| 50.95 | | David Awde | Woking AC | Woking | 2 Sep | | |