BT attracted nearly three-quarters of new broadband customers in the final quarter of 2015.
According to the broadband provider, the overall UK broadband market grew by 182,000 between October and December last year. BT's share was 130,000 - or 71 per cent.
Figures published in BT's latest trading statement also revealed that it had 3.7 million retail fibre broadband customers at the end of 2015 - with 250,000 being added in the final quarter.
Overall, some 494,000 new customers signed up for Openreach fibre broadband - a 32 per cent increase year-on-year, with the remaining 244,000 signing up with other internet service providers including BT subsidiary Plusnet, as well as TalkTalk and Sky.
This strong performance in the broadband market helped BT see pre-tax profits go up by almost a quarter during the final quarter of 2015 to £862 million, while revenues increased by three per cent to £4.5 million - the strongest increase in more than seven years.
Gavin Patterson, Chief Executive of BT, commented: "This is a strong set of results. Customers like what we’re offering.
"Fibre is underpinning the growth at Openreach with almost half a million premises taking up the service this quarter via dozens of service providers."
Mr Paterson said BT's superfast fibre broadband network is now available to more than 24 million homes and businesses across the country.
As a result, he believes fibre coverage will extend to 95 per cent of the UK by the end of next year.
Mr Paterson went on to confirm that BT plans to "go even further", as its G.fast trials are currently going well.
"The UK is poised to take the important journey from superfast to ultrafast broadband and BT is well placed to lead the charge," he said.
Mr Paterson added that service is a priority for the company, which is apparent in the creation of 1,000 extra contact centre jobs across Britain.
This, he said, will help it meet its commitment to answer more than 80 per cent of customer calls from within the UK by the end of 2016.