BT has launched an initiative to promote its new super-fast fibre service, but has remained vague about when the service will become available.
The company said that people signing up to one of its bundled services will get the chance to upgrade to BT fibre services for free when they go live in their area.
However, BT was unable to say when this might be, confirming only that it is likely to be before 2015.
"Fibre is the future of broadband, and BT is raising the speed and standard for customers nationwide. BT Infinity is head and shoulders above other services when it comes to value," said John Petter, managing director of BT's Consumer division.
"We are the only company offering an upgrade to fibre for no extra monthly cost, and the only company to offer free line installation across all new bundles."
However, BT would not give concrete dates for when this might happen, saying that the firm is on track to enable approximately two thirds of UK homes by 2015 and had committed some £2.5bn to the initiative.
BT has brought fibre connections to 1.5 million UK premises, and a spokesman told V3.co.uk that the figure will rise to 10 million by 2012 and 16.5 million by 2014.
Until then, the firm promised that its Infinity service will offer downstream speeds of up to 40Mbit/s and upstream of 10Mbit/s, which it said compares more than favourably with competing offers.
The service has come in for criticism by regulators, however. Last month the Advertising Standards Authority told BT to stop running adverts claiming that it can provide 'instant' internet services with Infinity.
Customers will be able to switch to this service "for no extra monthly cost when fibre becomes available in their area", according to BT. Customers can check whether it is available in their area on the Infinity web site.
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