British Telecom's new high-speed internet service provider, Open World, goes live today, offering connections at 10 times the speed of standard online services.

The venture is a crucial element in BT's internet strategy - the group's embattled chief executive, Sir Peter Bonfield, has been criticised for losing ground in cyberspace to other telecoms operators.

More than 100,000 people have pre-registered for Open World, which costs a flat rate of £39.99 a month and is targeted at businesses and home users.

The service is intended to overcome the problem of web pages taking several minutes to download, particularly when they include complicated pictures and detailed graphics.

The launch of Open World is earlier than expected, although only a few customers will be connected immediately. BT engineers have to visit each subscriber to establish a high-speed connection and the extent of the demand has created a long backlog.

An Open World spokesman said: "Like any kind of new technology, there has to be a waiting list. There is such demand that if you sign up tomorrow it may take until October to get a connection."

Furthermore, only a third of the country's telephone exchanges are capable of coping with the service, which could mean Open World is largely restricted to the south-east of England until modernisation takes place elsewhere.

Open World downloads data at a rate of 512 kilobytes a second - almost 10 times as fast as most existing service providers. BT hopes to have services soon at 1 megabyte or 2 megabytes a second.

The service will be a fresh test of the practicality of unmetered internet access - Open World subscribers will have a constant connection and will pay the same amount irrespective of how often they use the service.

This business model has failed to take off elsewhere - Alta Vista last week pulled the plug on an unmetered standard-speed service at £60 a year, saying it was uneconomical. It blamed BT, saying it it could not risk subsidising a free, unmetered package for customers while BT charged it by the minute for access to the telecoms network.

Sir Peter Bonfield will be looking for some good news - he is under pressure due to the company's plunging share price. Concerns about BT's expansion plans - and the impact on the company's gearing - caused the ratings agency Standard & Poor's to downgrade the company's grading this month.