By Jim Reed
Newsbeat technology reporter
BT is planning to spend £1.5bn to build a new "super-fast" broadband network across the UK over the next four years.
The telecoms company says the fibre-optic wires will deliver speeds of 100 megabits per second (Mbps), 12 times as fast as the advertised top speed on BT's current ADSL network.
BT said faster broadband would let customers run a number of different bandwidth-heavy applications at the same time.
New boss Ian Livingstone told the BBC: "You will be able to access multiple high definition TV streams and new applications like real time video conferencing and health services."
The new network is also designed to offer quicker "upstream" speeds, making it faster to post videos and use services like high definition gaming.
But BT says the £1.5bn investment will only go ahead if the telecoms regulator, Ofcom, lets it earn "a fair rate of return for shareholders", raising the possibility that, in the longer term, the price of broadband could rise.
The UK has been slower to invest in fast fibre-optic broadband than some other countries, with BT in particular cautious about spending the large sums involved in upgrading the network.
The fastest advertised speed on BT's ADSL network is currently 8Mbps although this could rise to 24Mbps in some areas by the end of the year at it rolls out a new ADSL2 service.
But there is a big gap between advertised and actual speeds with much resting on the distance between the computer or router and physical telephone exchange.
According to speedtest.net, a global speed test created by actual users, the real speed is closer to 3Mbps.
Countries like France, South Korea, France and Japan advertise speeds of up to 93Mbps with actual connections as high as 43Mbps.
BT's main British competitor, Virgin Media, has already built a fibre-optic network to most of its cable customers.
It offers speeds of 20Mbps although heavy users can see that figure reduced at busy times.
UK roll out
If the investment goes ahead, BT says the new network will cover 10 million British homes by 2012.
Most of those will continue to be connected to a local telephone "cabinet" by copper wires, limiting speeds to between 40 and 60Mbps but a million new homes could get fibre-optic cable directly, delivering 100Mbps speeds.
The company will start by upgrading its "back haul" network that connects telephone exchanges to the main internet data backbone in the UK.
Virgin Media are using a computer generated Mick Hucknall in adverts
Ian Livingstone said: "Soon you will see an uplift at peak times on existing copper which I know can be a problem for some customers."
The company will work with the Government and local authorities before deciding which areas of the UK will get the new network first.
"This isn't just about big cities, this is about what we can do for rural areas as well. If demand is there then BT will invest in that area," added Livingstone.
The faster network will also be available to 200 independent Internet Service Providers (ISPs) through BT's wholesale arm.
They can then resell faster broadband to their own customers.