BT is upgrading broadband speeds for some of its customers, from up to 8Mbps to 20Mbps, for free.

Following a successful trial, which saw the ISP offer 60,000 customers new ADSL2+ technology, BT said it planned to start rolling out the technology to all of its consumer and business customers.

Initially 549 telephone exchanges across the UK, which serve around 40 percent of the homes in Britain, will be given the technology. However, BT said it hoped that the service would reach 55 percent of British homes by 2010, depending upon consumer demand.

The ISP confirmed that consumers would see an increase in upload speed of up to 1Mbps. BT also said it plans to offer its Broadband Accelerator (also known as the BT I-Plate), which eliminates electrical interference from telephone-extension wiring to improve broadband speeds and reliability, free of charge to some customers.

"Unlike other providers, BT is upgrading customers to 20Mbps for free. High-speed broadband provides a faster and more reliable service that will transform the way we live, work, learn and play," said Gavin Patterson, chief executive officer, BT Retail.

Michael Phillips, product director at comparison website said BT's announcement was good news for consumers.

"Research we have conducted in the past has shown that broadband customers do not want to pay extra for a faster connection so BT has definitely upped the ante by giving a free broadband boost. Offering increased speeds at an existing price structure will put pressure on O2, Sky and Virgin Media who all charge a premium," Phillips added.