It believes G.fast can offer significant speed increases from existing and new fibre street cabinets, as well as at other points closer to the customer.
While G.fast is not true fibre to the premise, BT said this meant it could be deployed more efficiently and quickly.
Two pilot tests are to take place this summer in Huntingdon in Cambridgeshire and Gosforth in Newcastle with around 4,000 customers expected to participate.
If everything goes according to plan, BT hopes to begin deployment in 2016, with initial speeds of a few hundred megabits per second on offer at launch, rising to 500Mbps and beyond as the technology standard advances.
This would be substantially faster than the current Broadband Delivery UK superfast commitment of 24Mbps.
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BT CEO Gavin Patterson said the firm believes G.fast is key to unlocking ultrafast speeds and are prepared to upgrade large parts of its network if the pilots are successful.
“That upgrade will depend, however, on there continuing to be a stable regulatory environment that supports investment," he said.
“The UK is ahead of its major European neighbours when it comes to broadband and we need to stay ahead as customer demands evolve. G.fast will allow us to do that by building on the investment we have made in fibre to date. It will transform the UK broadband landscape from superfast to ultrafast in the quickest possible timeframe.”
Openreach reports solid fibre and landline growth
Alongside its ambitious broadband pledge, BT also announced its latest quarterly results, covering its third quarter to 31 December 2014, with its Openreach access unit the star of the show.
Openreach achieved the highest growth in the number of landlines on record, and it was also its best ever quarter for net new fibre broadband subscribers, although its sales were down.
BT’s other group business units, Global Services, Business, and Wholesale also saw their sales shrinking during the quarter, with only BT Consumer showing signs of growth.
The telecoms giant reported group revenues of £4.48bn, which was down 3% year-on-year and 1% on an underlying basis. Earnings before interest, taxes, depreciation and amortisation grew by 2% to £1.57bn, and adjusted pre-tax profit was up 13% to £814m.
BT also reported its acquisition of EE is proceeding according to plan, along with its own plans to launch a consumer mobile service.