Dido Harding, CEO of TalkTalk has criticised commitments made by BT Openreach to improve national broadband speeds, customer service and network coverage.
BT Openreach unveiled a new Customer Charter, which pledged to make improvements that would give some 10 million premises access to ultrafast speeds of between 300 and 500 Mbps by 2020.
It also said it was keen on giving "fibre broadband" connectivity to 95% of the UK, although it did concede that regulatory changes could be needed.
TalkTalk is one of several providers to have called for the separation of BT from Openreach and Ms Harding labelled the latest pledges as “weak” and lacking in ambition.
She told ISPreview: “We need to be much more ambitious than Openreach is suggesting. We should be investing in the very latest technology, delivering ultrafast fibre broadband straight into people’s homes, like TalkTalk, Sky and others are already rolling out across the country.
"Instead, BT Openreach’s plans for new products – G.Fast and XG.Fast – still rely on the old copper network.
"Their promises to improve customer service are also weak. For seven years now, Openreach has failed to meet the service targets in their contract with TalkTalk.
"This affects the service our customers receive, and damages our business in the process. But their charter only promises to meet Ofcom’s minimum service standards, far below what they have already committed to deliver for us. This situation can’t go on."
Despite her criticism, Ms Harding said TalkTalk was still willing to work with Openreach to "transform the UK’s broadband network".