The dogged Professor Bryan Carsberg and his Office of Telecommunications had three blows for British Telecom on Monday. As well as confirming that Mercury Communications will be permitted to compete with British Telecom on payphones, he is initiating an investigation into Mercury’s complaint that it is connecting Mercury’s lines to its own too slowly, and is examining Telecom’s rate of return, which he reckons breached the pre-set 19% limit in the company’s first half to September. Telecom admits that the rate was 20.2% during the half, and a freeze on prices for inland services is likely to bring the rate for the full year back down to about the 19% level. On payphones, the result of the first monthly joint study of the service with Telecom showed that of 7,000 visited, 24.2% were out of order – and only 2.4% of the faults were down to vandalism. Mercury plans to begin installing payphones next year, in sites close to its network.