British Gas Trading, the consumer marketing arm of Centrica, plans to compete in the domestic electricity sector, positioning itself as a one-stop energy supplier. The consumer electricity market will be opened to competition next April and Centrica aims to carve itself a substantial slice of the business, at the same time clinging-on to its existing gas customers when the next phase of gas supply deregulation comes into force in November. Centrica's move is said to be welcomed by the DTI which was getting increasingly twitchy at the apparent lack of interest in the electricity supply market by big players. Meantime, two of Centrica's main rivals have merged in a strategic alliance to create a more powerful marketing presence. German-owned supplier Amerada Hess has acquired Western Gas from US-owned South-Western Electricity, although the latter will continue to market its gas products. However, BG's main competitor in the deregulated regions remains Calortex, the jointly-owned Calor Gas/Texaco alliance.