Opal Telecom, the fixed-line subsidiary of The Carphone Warehouse, has agreed to buy the Airtime Group Limited (TAG). TAG is part of Canisp plc, which says it's selling the company because TAG can only achieve the required efficiencies within a larger organisation. TAG supplies fixed-line communications services to corporate and residential customers in the UK; its most recent annual results (31 March 2008) show a loss after tax of £50,829 on turnover of £2,592,996. [Carphone Warehouse press release; Canisp press release]