EXHIBIT 21 SUBSIDIARIES OF NTL INCORPORATED All of the corporations listed below were organized in the United Kingdom. CableTel Newport CableTel South Wales Ltd. CableTel Cardiff Ltd. CableTel West Glamorgan Ltd. CableTel (UK) Limited CableTel Limited CableTel Surrey and Hampshire Limited CableTel Scotland Ltd. CableTel Glasgow CableTel Kirklees CableTel West Riding Limited CableTel Hertfordshire Limited CableTel Central Hertfordshire Limited CableTel North Bedfordshire Limited CableTel Telecom Supplies Limited CableTel Northern Ireland Limited CableTel Ventures Limited CableTel Investments Limited Cable Online Limited Columbia Management Limited Metro South Wales Limited Secure Backup Systems Limited Digital Television Network Ltd. Chamber OnLine Ltd. DTELS Ltd. Enablis Ltd. National Transcommunications Ltd. NTL Group Limited Ltd. NTL Insurance Ltd. NTL Investment Holdings Ltd. NTL Ltd. NTL Networks Ltd. NTL Trustees Ltd. All of the corporations listed below were incorporated in Delaware: OCOM Corporation NTL (UK) Group, Inc. (formerly CableTel (UK) Group, Inc., formerly OCOM Sub II, Inc.) L.D. Data, Inc. Cellular Paging, Inc. CableTel Programming, Inc. European CableTel, Inc. CableTel Ventures Limited