Energis Ltd, the long-distance telecommunications carrier owned by the National Grid Co Ltd, has reached an interconnection agreement with Telecential Communications Ltd of Reading, Britain’s ninth-largest cable operator. The deal will enable outgoing calls placed by Telecential’s cable-telephony customers to pass directly to Energis without going through British Telecommunications Plc’s local loop. Telecential, owned by Telus Corp, a provincial telephone company in western Canada, and Shaw Communications, a Canadian cable company, has franchises in the Midlands, the South East and the South West. Currently, it has connected about 59,000 homes to its cable system, many of which take cable-telephony service as well. This may be a drop in the ocean compared with the 20m residential telephone lines in British Telecom’s portfolio, but British Telecom admits the emerging alliances between Energis and the cable companies present a potential threat to its market dominance. This would be an attack on us, said the company. Fuelling British Telecom’s fears are the claims by cable companies that they can undercut British Telecom by up to 25% on local calls, while Energis says its long-distance rates are between 10% and 40% cheaper than British Telecom’s. Further, the Cable Communications Association expects 1.2m cable-telephony lines to be in use by December 31, 1.8m by the end of 1996 and about 5m, or 25% of British Telecom’s total, by 2000. Also worrying British Telecom is the fact that, while Energis is limited in its service offerings, having no licence to offer overseas calls and therefore needing to buy capacity from British Telecom and other operators at retail rates, this is likely to change before the year is out. The company has applied for an international l icence and thinks there is a fair chance that it will be approved before the next election. In the meantime, Energis says it is expecting to sign more interconnection agreements with other cable franchises over the next few months. It did not name names, but it did admit that it has been holding talks with TeleWest Communications Plc.