[bbc] BT has launched a broadband service that offers speeds of up to 40 megabits per second (mbps).
Based around fibre optic cables, BT said the Infinity service could change the way that people use broadband.
It will give some customers an upload speed of up to 10 mbps.
Trials have been held in London's Muswell Hill, Whitchurch and Glasgow.
BT said 4 million homes and businesses would be able to get it by 2011.
The current highest speed service from BT available to homes is 20 megabits per second (mbps), though not all homes can get this headline speed.
BT Retail said the basic 40mbps service will be offered for £19.99 per month on an 18 month contract. It will also charge an installation fee of £50 for those on the lowest tariff.
Only those who opt for BT's most expensive tariff, £24.99 per month, will get the 10mbps upload speed. With the basic package upload speed is up to 2mbps.
BT said the higher speed would make it easier to share broadband among multiple computers and improve video streaming and net TV services.
As with lower speed services only those closest to the street cabinets that the fibre connects to are likely to get the full 40mbps.
A spokesman for Virgin Media wondered why anyone would buy a service from BT that has yet to launch when it could get higher speeds via cable already.
He said Virgin was already trialling future technology that could see cable speeds reach 200mbps.
BT puts price on higher speed broadband