TalkTalk and Sky have been criticised by BT's former Chief Executive for lobbying for the break-up of the organisation.
BT was ordered by Ofcom in July to give Openreach more independence and investment powers, so the broadband subsidiary could be run as a distinct and legally separate company with its own board.
However, the regulator stopped short of calling for a full structural separation, saying 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.
Nevertheless, TalkTalk and Sky are continuing to push for a full structural separation of BT and Openreach and are part of the Fix Britain's Internet campaign, along with Three and the Federation of Communication Services.
Lord Livingston of Parkhead, who left BT three years ago, has now intervened in the debate, saying TalkTalk and Sky's view that greater investment in fibre broadband is needed is hypocritical in light of their previous actions.
"I'm very perplexed about how history has been written," he told the Financial Times.
"BT was investing in fibre when Openreach's customers weren't interested."
Lord Livingston stated that neither Sky nor TalkTalk wanted to promote the move to superfast broadband eight years ago and that it was BT that took a lead on this technology.
"It is ironic, isn't it?" he observed.
TalkTalk responded by stating that it now offers the fastest fibre for the cheapest price anywhere in the country.
A spokeswoman said: "Far from holding the UK back, we’re putting our money where our mouth is and investing in a pure fibre future. Meanwhile, BT keeps Openreach shackled to copper, leaving the UK with just two per cent real fibre, compared to 60 per cent in Lithuania."