Sky has reaffirmed its view that Openreach should be truly independent from BT.
According to Andrew Griffith, Chief Operating Officer at Sky, a fully independent Openreach would have a clear purpose - treating all of its customers equally and raising the quality of its service.
Writing in the Telegraph, he also argued that a separated Openreach would be able to reinvest its profits in improving the network rather than fund other projects, as well as create value for BT shareholders.
"There is a fundamental conflict of interest while Openreach remains vertically integrated within BT Group," Mr Griffith commented.
"Far from investing in the network, BT is actually a net recipient of cash from Openreach. It therefore has no incentive to invest more. Customers suffer and there is no motivation to improve its notoriously poor service. This is simply not good enough."
Mr Griffith went on to warn that Britain is at risk of falling behind other nations, as it dropped down one place in Akamai's latest rankings of average fixed line broadband download speeds across the globe.
"As we prepare for a post-Brexit world, Britain needs to be even more productive to prosper," he said.
"To be competitive, we must ensure that we have the right core infrastructure in place - including our broadband, which underpins our digital economy and plays an ever-increasing role in our everyday lives."
However, Mr Griffith believes BT has underinvested in fibre technology and is continuing to "sweat its existing copper network".
This, he stated, meant that just two per cent of households in the UK had access to fibre to the home last year.
"Plans to increase coverage are lacking in ambition," Mr Griffith continued.
"The reality Ofcom must now confront is that, for Britain, it is a matter of when, and not if, Openreach becomes a truly independent business."
He added that if Ofcom is unwilling to take action, the government must look at what needs to be done so the "crucial task of building the digital infrastructure that our nation needs" can move forward.
Ofcom has ordered BT to give more independence and investment powers to Openreach, with the broadband subsidiary being run as a distinct and legally separate company with its own board.
The watchdog believes its proposals will provide Openreach with the greatest possible degree of independence without separating the companies entirely, and lead to decisions being taken for the good of its customers and the wider telecoms industry.
The Fix Britain's Internet campaign - an industry coalition consisting of Sky, TalkTalk, Vodafone, Three UK and the Federation of Communication Services - is currently pushing for a full structural separation and urged internet users who are unhappy with the service they receive to respond to Ofcom's consultation on the proposed Openreach reforms.