BT’s plan to upgrade 25m homes and business to full-fibre by 2026 would now be solely delivered by Openreach, he added.
Mr Jansen also said some customers would be hit with higher prices as inflation is poised to rise by 4pc next year, according to the Office for Budget Responsibility.
BT announced in March that new and renewing customers would stomach price rises of inflation plus 3.9pc.
On the fibre joint venture, Mr Jansen said: “Because of our balance sheet strength, the savings we have made over the past few years and the prospects moving forward, we can afford to do this additional 5m we announced in May to get to 25m by 2026.
“The great news is we can afford to fund it ourselves. After all the difficulty and questions [prior to getting regulator clarity from Ofcom], now we can see such a clear picture for the outlook, we believe our shareholders should maintain 100pc of the benefit.”
BT, which has been working through 13,000 job cuts, confirmed a Telegraph report that it had delivered £1bn in savings 18 months early at a lower cost of £571m compared to a previous forecast of £900m.
The improved picture prompted BT to bring forward its target of cutting £2bn of costs each year to 2024 from 2025, with capital expenditure expected to be £200m lower at £4.8bn from 2023.
Mr Drahi, the founder of the French broadband challenger Altice, owns a 12pc stake in BT. He has been barred from bidding for BT until December after saying in June that he had no intention to make an offer.
Mr Jansen said “nothing’s changed” in BT’s approach since the arrival of Mr Drahi on the shareholder register and that all big shareholders fully support BT’s strategy.
BT revenues fell 3pc to £10.3bn for the six months to September as a stronger performance from Openreach failed to offset falls across its business connectivity arm and global IT services operation.