BT says it is speeding up its rollout of full-fibre broadband to five million more households than previously planned in a move it says could create up to 7,000 jobs.
Boss Philip Jansen told the BBC that BT is also bringing forward its deadline to complete the work, with 25 million homes now due to be connected by 2026.
"It's a massive programme - a £15bn investment," he said.
The telecoms giant has been criticised for the pace of full-fibre rollout.
But BT said tax changes introduced on fibre broadband investment to homes and businesses allowed it to accelerate its strategy.
Mr Jansen added that the faster rollout could be done through joint ventures with other parties to share the work and investment with its Openreach operation, especially to speed up broadband access to people in rural areas.
A number of European telecoms rivals and private equity investors are thought to have looked at trying to secure a slice of the UK's fast-growing broadband infrastructure.
Accelerating the plans "will help fuel UK economic recovery, with better connectivity and up to 7,000 new jobs", Mr Jansen said.
Many big companies use the Openreach network to provide their services, including TalkTalk and Sky, but have been critical of the pace of the rollout and prices.
TalkTalk said it welcomed Thursday's announcement, but said that affordability and take-up of services was key. "Whilst this [BT] commitment is great progress, it shouldn't hide the fact that the UK lags far behind other European nations in rolling out full fibre," a TalkTalk spokesperson said.
BT news came as Britain's biggest broadband and mobile provider reported a 23% fall in full-year pre-tax profit to £1.8bn, in large part due to a 7% fall in revenue to £21.3bn.
