Mercury has been at loggerheads for months with Oftel over the way BT charges other companies for use of its network. The company relies on BT to deliver local calls as direct connection to Mercury's network is largely limited to business customers.
The present method, approved by the regulator, forces Mercury to pay by the minute, which the company says ties its charges for customers to those charged by BT. Mercury wants to be able to buy capacity on BT's network in bulk, allowing it more flexibility in charging and offering price packages tailored to individual needs.
Maev Sullivan, Mercury's director of strategy and commercial planning, said: 'An effective interconnect regime is critical to the development of an open and lively competitive telecoms market, which is what UK customers were promised and what they deserve. It is frustrating that we have been pursuing this case since before Christmas and have still not passed beyond the procedural issues.'
Oftel, which is carrying out a review of the entire interconnection regime, has attacked the timing of Mercury's legal campaign as unhelpful. The regulator says it has been willing to look at any proposals that prove workable.
Separately, it emerged that Andy Sukawaty, the chief operating officer of Mercury's mobile subsidiary, One-2-One, is leaving the company.
Mr Sukawaty is to become chief executive of National Transcommunications, the former engineering arm of the Independent Broadcasting Authority. He led negotiations that resulted in the formation of One-2-One, a 50/50 joint venture between Mercury's parent, Cable and Wireless, and US West.