Ofcom has announced proposals to allow BT to offer large business customers bespoke call prices, which should lead to discounts for some companies.
Currently, BT must offer all large business customers the same published call and line charges.
Under the regulator's proposals, BT would be allowed to agree individual terms with business customers spending more than £1m a year on telecommunications services, without having to publish its prices.
Ofcom said it anticipates that the measures will stimulate greater competition in the fixed-line market, as well as supporting a potential reduction in BT's prices for large business customers.
Ofcom is also seeking to ensure that BT's competitors are able to operate on equal terms with BT.
A consultation document on the proposals has suggested that before BT can introduce bespoke pricing competitors must be able to replicate BT's services using BT's wholesale line rental service and carrier pre-selection products.
In a separate move, Ofcom has also placed a ceiling on how much BT can charge its competitors for renting its broadband lines, to enable them to offer separately branded broadband services to customers.