Less than two weeks before switch-off, BT released research claiming that about 70 per cent of its customers still quoted 192 when asked what number they should call to reach directory enquiries.
The research indicates that the multimillion-pound advertising campaigns launched by BT's competitors to get consumers to remember their service numbers have largely failed.
The two companies that hit the market with the largest campaigns were the US company InfoNXX, which operates as The Number and uses the 118 118 moustachioed runners developed by WCRS, and the Irish company Conduit, which used superhero characters to promote 11 88 88 through Euro RSCG Wnek Gosper Partners.
With their advertising campaigns kicking off months in advance of switch-off, the new entrants hit the consumer market early with heavyweight activity boasting a combined marketing budget of more than £40 million.
Julian Hough, the new-business director at WCRS, defends the strategy used to promote 118 118, which uses the most in-your-face creative of all the players, saying it is about brand building.
"We decided that we wanted to go early with the advertising and establish the brand to distinguish it from BT and position The Number as a more dynamic, innovative company. It's not just about number memorability and usage rates have exceeded all expectations."
BT, which will operate its own directory enquiries service under the number 118 500, has employed a very different strategy from its rivals. The telecoms giant has only just launched its main campaign, which broke last weekend, reasoning that consumers aren't likely to pay attention much before switch-off.
"The others are unknown and have to build awareness and credibility. We are heavily pushing the BT brand because people know and trust us - we are more than just a number," Simon Lubin, the head of marketing for BT directory services, says. "Our view is that it is a low-interest category where people will only call when they need a number and won't react until it is switched off. Our research shows that the ads are working on a general awareness level only and not on a brand or service level."
Neil Christie, the marketing director at Euro RSCG, refutes the importance of pushing the brands, arguing that people mainly care about the price.
"We aren't talking about a bank: it is about directory enquiries and the average punter doesn't care who they get the service from. It is like turning on a tap: no-one cares who provides the water," he says.
"We are trying to get people to change the habit of a lifetime," he adds.
But BT's research doesn't appear to reflect the full story.
According to research from the regulator Oftel, which drove through the deregulation programme, a far larger chunk of the consumer market is aware of the new brands than BT claims.
In fact, Oftel claims that more than 80 per cent of consumers are aware that there is a range of numbers for directory enquiries and that up to 30 per cent of people dialling directory enquiries are already using the new numbers.
Of course, the research aside, the true test of the various advertising strategies will only come when consumers are forced into making provider decisions after switch-off.
118099 Cable & Wireless
118800 Directory Enquiries UK
118866 Double One, Double Eight, Double Six
118811 One, The Number
118499 Share UK
118180 Telewest Broadband
118118 The Number
118247 Yellow Pages
118404 Ymholiadau Rhifau Ffon BT Y Du