Cable and Wireless Plc’s Mercury Communications has signed a tripartide agreement to lay an underwater fibre optic cable between the UK, France and Portugal with the French and Portuguese PTTs. The 140Mbits-per-second unrepeated line is expected to be completed by early 1989. Mercury chief executive Gordon Owen yesterday described the agreement as a major step into Europe. As yet, however, no agreement on sending traffic down the cable has been worked out, a situation Owen described as only possible with the French and ama zing. The UK-France line will give French callers access to the transatlantic PTAT cable, when the latter comes on stream in mid-1989. Mercury also announced yesterday that Hull Telephone subscribers are able to make trunk calls over the Mercury network with immediate eff ect. Gordon Owen also used the opportunity afforded by Cable and Wireless’s interim results to launch a bitter attack on British Telecom – details are in page five.