Updated BT has been rapped by the UK's advertising watchdog, which found that the national telco had "misled" customers about when its broadband products would be available in their areas.

The Advertising Standards Authority upheld complaints submitted by 15 people, who griped about BT because its "availability checker" website for its Infinity and Total Broadband products, in some instances, repeatedly pushed back the dates over a long period of time.

BT's £2.5bn fibre network upgrade to two-thirds of homes and businesses across Britain is mainly being fed from the local exchange to streetside cabinets - the service is then carried into homes and businesses via a copper phone line.

The FTTC Infinity product boasts theoretical download speeds of up to 80Mbps and upload speeds of 20Mbps. But some customers have been disappointed to discover that BT's tracker explaining when that product should be available was seemingly telling porkies by regularly postponing the dates.

By way of example, the ASA said one complainant had been told on the site that Infinity would be available on 30 September 2012, only to then discover months later that the date had changed to 31 December 2012.

While the website has recently begun telling customers using the checker that: "When we are able to provide a date for future fibre availability, it is indicative only and subject to change", that newly placed disclaimer was not enough to satisfy the ASA.

The watchdog said in its adjudication:

We considered that the appearance of a date or provisional date in the availability checker suggested that active plans were in place to roll out BT Infinity in that area and that the service would therefore be available on or around that time, and the listed date should not be subsequently or regularly pushed back. We noted we had not seen supporting documentation showing that, in each of the areas where the complainants were based, the listed date in the availability checker was based on scheduled plans for Openreach to have BT Infinity available in those areas on or around the listed dates. We considered that the date BT Infinity was expected to be available in their area would be a material consideration for consumers when deciding whether to register an interest in the service. Because we had not seen documentation that showed there were scheduled plans to roll out BT Infinity in the complainants' areas and make BT Infinity available in those areas on or around the listed dates, and because we understood that, in at least one case, there were currently no plans for BT Infinity to be rolled out in an area while the availability checker listed a provisional date that was less than three months away, we considered that the inclusion of provisional dates was likely to mislead.

It concluded that the ad could not be substantiated and was considered to be misleading. The ASA said BT's claim must not appear again in its current form. Dates were only allowed to be included, the regulator ruled, if BT's Openreach division had actually scheduled plans to work on the service in the corresponding area.

BT, for its part, said it had already made "significant changes" last October to the wording on its website to make it clear that the dates were only provisional. A new online checker is being built for BT, which will apparently be implemented in the next few months.

It's not the first time BT has got its facts wrong about where and when customers could expect to see their broadband products upgraded to faster broadband.

Last September, we reported that the company's "Where and When" website was blighted by a dodgy bug in the postcode checker system, which placed Islington in South Africa and Shoreditch on Mount Everest. ®

Updated to add

BT has been in touch since the publication of this article to give us this statement:

This is a disappointing ruling. People clearly want to know when fibre might become available in their area and so BT has been publishing its best estimates on a regular basis. Those plans sometimes have to change however if local planning permission isn’t granted or we find that a third party can’t meet our deadlines.

Fifteen complaints is a tiny number when you consider that BT is enabling tens of thousands of cabinets, but we will work with the ASA to make changes where we can as it is clear that people remain keen to know when fibre might reach them.