BT is to extend access to higher-speed 20Mbps copper-based broadband to an additional 2.5 million premises by spring 2013.
The telecoms giant says around 90% of UK premises will receive the upgrade, instead of the original target of 80%, bringing the service to a total of 22.5 million premises. The firm claims that many customers will see broadband speeds double.
Of the extra 800 exchanges affected, 400 are located in rural areas, serving over 900,000 premises. BT has been criticised by rural broadband campaigners for slow broadband and the lack of fibre upgrades being rolled out in harder-to-reach areas.
Alex Pannell, director of product management at BT Wholesale, said: "This is a significant expansion of our roll-out plan and is further proof of our commitment to serve rural areas. The faster speeds will support the government's aim of enhancing broadband speeds for both town and countryside."
Industry regulator Ofcom recently forced BT to reduce the prices it charges internet service providers in rural areas, to help provide cheaper broadband access to three million homes and businesses.
BT is also rolling out superfast fibre-to-the-cabinet broadband to two-thirds of UK premises by the end of 2015, in a £2.5bn programme, and is bidding for government funds to extend fibre services more widely in areas where it is not otherwise commercially viable to do so.
The UK is lagging behind several international rivals in the global league table for average broadband speeds.