| 01904 200 | Redwood Technologies Ltd | 15/11/2018 |
| 01904 201 | TelNG Limited | 01/03/2007 |
| 01904 202 | Voiceflex Limited | 30/07/2007 |
| 01904 203 | (AQ) LIMITED | 27/09/2012 |
| 01904 204 | Localphone Limited | 23/05/2007 |
| 01904 205 | Net-Work Internet Ltd | 21/09/2007 |
| 01904 206 | TalkTalk Communications Limited | 12/02/2013 |
| 01904 207 | VoiceHost Limited | 22/06/2010 |
| 01904 208 | Nationwide Telephone Assistance Ltd | 22/10/2007 |
| 01904 209 | Resilient PLC | 05/01/2007 |
| 01904 210 | VoIP-Un Limited | 08/11/2007 |
| 01904 211 | Voxbone SA | 23/11/2007 |
| 01904 212 | Telecom2 Limited | 10/09/2009 |
| 01904 213 | Nodemax Limited | 14/07/2008 |
| 01904 214 | Digital Space Group Limited | 04/06/2008 |
| 01904 215 | Inet Telecoms Ltd (Voipfone) | 18/09/2008 |
| 01904 216 | Barritel Limited | 08/10/2008 |
| 01904 217 | York Data Services Limited | 11/11/2008 |
| 01904 218 | Served Up Limited | 17/10/2008 |
| 01904 220 | TalkTalk Communications Limited | 01/08/2019 |
| 01904 221 | Gamma Telecom Holdings Ltd | 04/01/2019 |
| 01904 222 | Dial 9 Communications Limited | 25/10/2019 |
| 01904 223 | Internetty Ltd | 01/06/2020 |
| 01904 225 | Daisy Communications Ltd | 14/12/2011 |
| 01904 226 | Daisy Communications Ltd | 14/12/2011 |
| 01904 227 | Daisy Communications Ltd | 14/12/2011 |
| 01904 228 | Daisy Communications Ltd | 14/12/2011 |
| 01904 229 | Daisy Communications Ltd | 14/12/2011 |
| 01904 23 | Gamma Telecom Holdings Ltd | 20/04/2004 |
| 01904 25 | TGL Services (UK) Ltd | 02/02/2015 |
| 01904 260 | Linear Telecoms Limited | 19/10/2010 |
| 01904 261 | Orbtalk Limited | 05/07/2011 |
| 01904 263 | Numbers Plus Ltd | 28/07/2011 |
| 01904 264 | Sky UK Limited | 27/06/2013 |
| 01904 266 | Media Hawk Ltd | 26/09/2011 |
| 01904 267 | Cloudcall Limited | 11/11/2011 |
| 01904 268 | Internexus Networks Limited | 22/11/2011 |
| 01904 269 | Sky UK Limited | 27/06/2013 |
| 01904 270 | TalkTalk Communications Limited | 26/01/2009 |
| 01904 271 | Affiniti Integrated Solutions Limited | 13/01/2009 |
| 01904 272 | TalkTalk Communications Limited | 06/01/2015 |
| 01904 273 | Solutios Limited | 26/11/2008 |
| 01904 274 | Sky UK Limited | 27/06/2013 |
| 01904 275 | Affiniti Integrated Solutions Limited | 13/01/2009 |
| 01904 276 | Affiniti Integrated Solutions Limited | 13/01/2009 |
| 01904 277 | Digital Space Group Limited | 15/03/2016 |
| 01904 278 | IPV6 Limited | 04/02/2009 |
| 01904 279 | I-NET COMMUNICATIONS GROUP PLC | 20/02/2009 |
| 01904 280 | Invade International Ltd | 13/01/2016 |
| 01904 283 | Digital Mail Limited | 13/01/2006 |
| 01904 284 | GTT-EMEA LTD | 14/10/2021 |
| 01904 287 | FleXtel Limited | 16/11/2005 |
| 01904 288 | Verizon UK Limited | 03/08/2005 |
| 01904 289 | TalkTalk Communications Limited | 19/06/2006 |
| 01904 290 | Digital Space Group Limited | 12/04/2016 |
| 01904 292 | Virgin Media Limited | 21/03/2014 |
| 01904 293 | Colt Technology Services | 11/05/2006 |
| 01904 294 | Virgin Media Limited | 31/08/2006 |
| 01904 295 | TTNC Limited | 15/11/2013 |
| 01904 296 | Six Degrees Technology Group Limited | 14/01/2020 |
| 01904 297 | Spitfire Network Services Limited | 30/08/2006 |
| 01904 298 | Virgin Media Limited | 31/08/2006 |
| 01904 299 | Vodafone Ltd (C&W) | 18/06/2013 |
| 01904 300 | Intrado Cloud Solutions Limited | 02/08/2010 |
| 01904 301 | Nexbridge Communications Limited | 10/01/2012 |
| 01904 303 | Tuxtel Ltd | 21/12/2011 |
| 01904 304 | Hello Telecom (UK) Limited | 01/02/2012 |
| 01904 306 | Bicom Systems EURL | 01/03/2012 |
| 01904 307 | ICC Networks Ltd | 18/04/2012 |
| 01904 308 | Citrus Telecommunications Ltd | 28/02/2012 |
| 01904 309 | API Telecom Limited | 19/04/2012 |
| 01904 310 | Telappliant Ltd | 03/02/2009 |
| 01904 311 | Mars Communications Limited | 19/02/2009 |
| 01904 312 | Relax Telecom Limited | 15/08/2014 |
| 01904 313 | Andrews & Arnold (Numbers) Ltd | 09/04/2009 |
| 01904 314 | Telecoms World PLC | 02/07/2009 |
| 01904 315 | Vectone Mobile Limited | 01/07/2009 |
| 01904 317 | CFL Communications Ltd | 21/07/2009 |
| 01904 318 | Nexus Telecommunications Limited | 07/10/2009 |
| 01904 319 | TeleWare Group PLC | 27/01/2010 |
| 01904 32 | Affiniti Integrated Solutions Limited | 10/05/1999 |
| 01904 33 | Virgin Media Limited | 16/05/1995 |
| 01904 34 | Virgin Media Limited | 16/05/1995 |
| 01904 35 | Vodafone Ltd (Energis) | 26/05/2006 |
| 01904 360 | GCI Network Solutions Ltd | 02/05/2017 |
| 01904 365 | GCI Network Solutions Ltd | 26/06/2018 |
| 01904 372 | WIGHTFIBRE LIMITED | 12/01/2010 |
| 01904 373 | Buzz Networks Limited | 24/02/2010 |
| 01904 374 | Atomstream Limited | 12/04/2010 |
| 01904 375 | Liquid 11 Limited | 19/04/2010 |
| 01904 376 | Calltracks Limited | 20/09/2013 |
| 01904 377 | Suretec Systems Ltd | 13/05/2010 |
| 01904 378 | Numbergroup Utilities Ltd | 02/11/2010 |
| 01904 379 | Vonage Limited | 26/01/2015 |
| 01904 380 | Lumen Technologies UK Limited | 11/04/2006 |
| 01904 381 | Lumen Technologies UK Limited | 11/04/2006 |
| 01904 382 | Lumen Technologies UK Limited | 11/04/2006 |
| 01904 383 | Lumen Technologies UK Limited | 11/04/2006 |
| 01904 384 | Lumen Technologies UK Limited | 11/04/2006 |
| 01904 385 | Lumen Technologies UK Limited | 11/04/2006 |
| 01904 386 | Lumen Technologies UK Limited | 11/04/2006 |
| 01904 387 | Commi Holdings Limited | 21/11/2016 |
| 01904 388 | Lumen Technologies UK Limited | 11/04/2006 |
| 01904 389 | Lumen Technologies UK Limited | 11/04/2006 |
| 01904 390 | Windsor Telecom Ltd | 22/07/2010 |
| 01904 391 | Media Telecom Ltd | 05/08/2010 |
| 01904 393 | IP Wholesale Limited | 01/06/2017 |
| 01904 394 | Verizon UK Limited | 23/07/2010 |
| 01904 395 | Invosys Limited | 10/04/2012 |
| 01904 396 | 24 SEVEN CLOUD COMMUNICATIONS LTD | 30/09/2019 |
| 01904 397 | Firstsound Ltd | 11/04/2011 |
| 01904 398 | Minotaur Telecom Limited | 01/02/2013 |
| 01904 399 | Sky UK Limited | 27/06/2013 |
| 01904 400 | BT | 15/07/1994 |
| 01904 401 | BT | 15/07/1994 |
| 01904 403 | BT | 15/07/1994 |
| 01904 404 | BT | 15/07/1994 |
| 01904 405 | BT | 15/07/1994 |
| 01904 406 | BT | 15/07/1994 |
| 01904 407 | BT | 15/07/1994 |
| 01904 408 | BT | 15/07/1994 |
| 01904 409 | BT | 15/07/1994 |
| 01904 41 | BT | 15/07/1994 |
| 01904 42 | BT | 15/07/1994 |
| 01904 43 | BT | 15/07/1994 |
| 01904 44 | BT | 15/07/1994 |
| 01904 45 | Vodafone Ltd (C&W) | 09/09/2013 |
| 01904 460 | BT | 15/07/1994 |
| 01904 461 | BT | 15/07/1994 |
| 01904 462 | BT | 15/07/1994 |
| 01904 463 | BT | 15/07/1994 |
| 01904 464 | BT | 15/07/1994 |
| 01904 465 | BT | 15/07/1994 |
| 01904 466 | BT | 15/07/1994 |
| 01904 468 | BT | 15/07/1994 |
| 01904 469 | BT | 15/07/1994 |
| 01904 47 | BT | 15/07/1994 |
| 01904 48 | BT | 15/07/1994 |
| 01904 49 | BT | 15/07/1994 |
| 01904 50 | AQL Wholesale Ltd | 01/11/2004 |
| 01904 510 | Vodafone Ltd (C&W) | 09/09/2013 |
| 01904 511 | Vodafone Ltd (C&W) | 09/09/2013 |
| 01904 512 | Vodafone Ltd (C&W) | 09/09/2013 |
| 01904 513 | Vodafone Ltd (C&W) | 09/09/2013 |
| 01904 514 | Vodafone Ltd (C&W) | 09/09/2013 |
| 01904 515 | Vodafone Ltd (C&W) | 09/09/2013 |
| 01904 516 | Vodafone Ltd (C&W) | 09/09/2013 |
| 01904 52 | BT | 15/07/1994 |
| 01904 530 | Simwood eSMS Limited | 03/08/2010 |
| 01904 531 | Core Telecom Limited | 06/08/2010 |
| 01904 532 | Plus Telecom Limited | 24/09/2010 |
| 01904 533 | Sky UK Limited | 27/06/2013 |
| 01904 534 | Telephone Box Limited | 10/12/2010 |
| 01904 54 | BT | 30/08/1995 |
| 01904 55 | BT | 15/07/1994 |
| 01904 56 | Affiniti Integrated Solutions Limited | 15/07/1994 |
| 01904 570 | Inclarity Communications Limited | 08/11/2012 |
| 01904 571 | Inclarity Communications Limited | 08/11/2012 |
| 01904 572 | Inclarity Communications Limited | 08/11/2012 |
| 01904 575 | Inclarity Communications Limited | 08/11/2012 |
| 01904 58 | Redcentric Solutions Limited | 05/06/2015 |
| 01904 590 | Ziron Limited | 01/08/2012 |
| 01904 591 | Sky UK Limited | 27/06/2013 |
| 01904 592 | Orange Business Holdings UK Limited | 19/07/2012 |
| 01904 593 | TalkTalk Communications Limited | 14/09/2012 |
| 01904 594 | Sky UK Limited | 27/06/2013 |
| 01904 595 | IOVOX Limited | 04/07/2012 |
| 01904 597 | Content Guru Limited | 11/10/2012 |
| 01904 598 | Numbergroup Utilities Ltd | 29/04/2019 |
| 01904 599 | Invoco Ltd | 22/05/2012 |
| 01904 600 | BT | 15/07/1994 |
| 01904 601 | BT | 15/07/1994 |
| 01904 602 | BT | 15/07/1994 |
| 01904 603 | BT | 15/07/1994 |
| 01904 604 | BT | 15/07/1994 |
| 01904 605 | BT | 15/07/1994 |
| 01904 606 | BT | 15/07/1994 |
| 01904 607 | BT | 15/07/1994 |
| 01904 608 | BT | 15/07/1994 |
| 01904 61 | BT | 15/07/1994 |
| 01904 62 | BT | 15/07/1994 |
| 01904 63 | BT | 15/07/1994 |
| 01904 64 | BT | 15/07/1994 |
| 01904 65 | BT | 15/07/1994 |
| 01904 66 | BT | 15/07/1994 |
| 01904 67 | BT | 15/07/1994 |
| 01904 68 | BT | 15/07/1994 |
| 01904 69 | BT | 15/07/1994 |
| 01904 70 | BT | 15/07/1994 |
| 01904 71 | BT | 17/12/1997 |
| 01904 720 | BT | 15/07/1994 |
| 01904 721 | BT | 15/07/1994 |
| 01904 723 | BT | 15/07/1994 |
| 01904 724 | BT | 15/07/1994 |
| 01904 725 | BT | 15/07/1994 |
| 01904 726 | BT | 15/07/1994 |
| 01904 727 | BT | 15/07/1994 |
| 01904 728 | BT | 15/07/1994 |
| 01904 73 | BT | 15/07/1994 |
| 01904 744 | BT | 15/07/1994 |
| 01904 749 | BT | 15/07/1994 |
| 01904 75 | BT | 15/07/1994 |
| 01904 76 | BT | 15/07/1994 |
| 01904 77 | BT | 15/07/1994 |
| 01904 78 | BT | 15/07/1994 |
| 01904 79 | BT | 15/07/1994 |
| 01904 800 | Media Hawk Ltd | 25/11/2015 |
| 01904 801 | TalkTalk Communications Limited | 04/12/2015 |
| 01904 802 | Media Hawk Ltd | 02/12/2015 |
| 01904 803 | Gamma Telecom Holdings Ltd | 29/02/2016 |
| 01904 804 | Alnitak GmbH | 07/12/2015 |
| 01904 806 | NFON UK Ltd | 29/04/2016 |
| 01904 808 | I.T Communications Limited | 09/11/2015 |
| 01904 809 | Gamma Telecom Holdings Ltd | 14/09/2016 |
| 01904 81 | Vodafone Ltd (C&W) | 09/09/2013 |
| 01904 82 | Vodafone Ltd (C&W) | 09/09/2013 |
| 01904 83 | Syntec Limited | 01/03/2005 |
| 01904 848 | TalkTalk Communications Limited | 31/08/2011 |
| 01904 849 | TalkTalk Communications Limited | 31/08/2011 |
| 01904 85 | Vodafone Ltd (Thus) | 26/01/2012 |
| 01904 860 | Phone Co-Op Numbering Limited | 23/12/2010 |
| 01904 861 | Sky UK Limited | 20/06/2013 |
| 01904 862 | Kalnet4U Ltd | 04/06/2013 |
| 01904 863 | TalkTalk Communications Limited | 30/09/2013 |
| 01904 864 | TalkTalk Communications Limited | 03/06/2014 |
| 01904 865 | Sky UK Limited | 15/09/2014 |
| 01904 866 | iHub 2 Limited | 18/05/2016 |
| 01904 867 | Sky UK Limited | 15/08/2013 |
| 01904 868 | Sky UK Limited | 15/08/2013 |
| 01904 869 | XoverX Ltd | 26/04/2013 |
| 01904 87 | BT | 19/05/1999 |
| 01904 88 | BT | 15/07/1994 |
| 01904 890 | Magrathea Telecommunications Limited | 17/11/2011 |
| 01904 891 | Magrathea Telecommunications Limited | 17/11/2011 |
| 01904 894 | Magrathea Telecommunications Limited | 17/11/2011 |
| 01904 896 | Magrathea Telecommunications Limited | 17/11/2011 |
| 01904 897 | Magrathea Telecommunications Limited | 17/11/2011 |
| 01904 898 | Magrathea Telecommunications Limited | 17/11/2011 |
| 01904 899 | Magrathea Telecommunications Limited | 17/11/2011 |
| 01904 900 | YayYay Limited | 24/04/2015 |
| 01904 901 | Metronet (UK) Limited | 21/05/2019 |
| 01904 903 | Sky UK Limited | 02/09/2015 |
| 01904 904 | Lanonyx Telecom Limited | 03/03/2015 |
| 01904 906 | Sky UK Limited | 19/10/2015 |
| 01904 907 | Sky UK Limited | 19/10/2015 |
| 01904 908 | Aloha Telecommunications Ltd | 10/09/2015 |
| 01904 909 | Colt Technology Services | 07/05/2015 |
| 01904 910 | Belgacom International Carrier Services SA | 20/06/2016 |
| 01904 911 | DIDWW Ireland Limited | 16/11/2016 |
| 01904 912 | Sky UK Limited | 03/10/2016 |
| 01904 913 | Adepteo Limited | 29/11/2016 |
| 01904 914 | TalkTalk Communications Limited | 07/04/2017 |
| 01904 915 | Hyperoptic Ltd | 27/10/2017 |
| 01904 916 | Fuse 2 Communications Ltd | 03/07/2017 |
| 01904 917 | Gamma Telecom Holdings Ltd | 04/04/2017 |
| 01904 918 | IOVOX Limited | 31/01/2017 |
| 01904 919 | Number Services Ltd. | 22/11/2018 |
| 01904 920 | Entanet International Ltd | 05/12/2017 |
| 01904 921 | TalkTalk Communications Limited | 14/12/2017 |
| 01904 922 | IP Voice Networks Ltd | 20/09/2017 |
| 01904 923 | Zapappi Ltd | 05/01/2018 |
| 01904 924 | Colt Technology Services | 12/09/2017 |
| 01904 925 | Club Communications Ltd | 13/08/2018 |
| 01904 926 | Calltracks Limited | 26/10/2018 |
| 01904 927 | TalkTalk Communications Limited | 21/11/2018 |
| 01904 928 | BT | 17/12/2018 |
| 01904 929 | Gamma Telecom Holdings Ltd | 02/08/2017 |
| 01904 930 | WIZE ANALYTICS LIMITED | 29/04/2019 |
| 01904 931 | TalkTalk Communications Limited | 13/01/2020 |
| 01904 932 | Gamma Telecom Holdings Ltd | 22/09/2021 |
| 01904 933 | BT | 23/09/2020 |
| 01904 934 | Colt Technology Services | 05/04/2019 |
| 01904 935 | Twilio Ireland Limited | 13/10/2020 |
| 01904 936 | BT | 05/07/2021 |
| 01904 938 | TELNYX UK LIMITED | 07/05/2020 |
| 01904 941 | SiPalto Ltd | 23/01/2020 |
| 01904 942 | BT | 03/05/2019 |
| 01904 943 | Gamma Telecom Holdings Ltd | 12/04/2021 |
| 01904 944 | ICUK Computing Services Limited | 12/08/2019 |
| 01904 945 | Mi Telecom Limited | 06/07/2020 |
| 01904 946 | Gamma Telecom Holdings Ltd | 16/09/2020 |
| 01904 947 | BT | 28/04/2020 |
| 01904 948 | Gamma Telecom Holdings Ltd | 23/04/2020 |
| 01904 949 | Gamma Telecom Holdings Ltd | 04/11/2019 |
| 01904 952 | Colt Technology Services | 05/07/2021 |
| 01904 955 | 24 Seven Communications Ltd | 13/10/2021 |
| 01904 959 | KCOM Group Limited | 27/05/2021 |