BT has admitted that the level of demand it insists on for extending ADSL roll-out to rural areas is higher than necessary to cope with "drop outs".
ISPs, MPs and the government's chief independent advisor on broadband have attacked BT for being too conservative, and have asked that regulator Oftel review the company's figures.
BT has received subsidies to fund ADSL expansion in rural areas. It has eight partnerships with coalitions of agencies and commerce groups in remote areas, saving up to 85 per cent of investment costs. It now wants rural customers to effectively guarantee its revenue streams before offering ADSL.
On 1 July, BT established a registration scheme demanding that between 200-500 customers sign up before an exchange could be ADSL-enabled.
It set levels for just 338 areas, despite promising in April to upgrade 500. BT hopes to set targets for 162 more exchanges this month, and a further 400 by September.
The telco has admitted that its levels include a 25 per cent margin so that "drop outs" scrapping orders do not affect revenue targets per exchange.
BT also wanted ISPs to provide a £100-per-lead indemnity against failed leads, but ISPs rejected the idea.
Bugs in the registration process have fuelled fears that BT is simply dragging its feet. Leading ISPs are nervous of BT's scheme.
One told vnunet.com: "It crashes at peak times, it delivers negative messages saying areas are unavailable when the system is down when they're not, and it appears to favour some ISPs."
But BT rejected this. "I'm not going to pretend the [registration] system hasn't taken a few hits because it has, but we genuinely do want this to work and complaining anonymously achieves nothing," David Orr, head of media relations, told vnunet.com.
"We'd be delighted to talk to those people who have issues; are they scared of us?"
But Sir George Young MP has called for Oftel to step in. "Oftel should commission an independent assessment of the investment cost and payback projections for enabling additional exchanges," he said.
"Some industry insiders have suggested to me that BT is only going through the motions - they suggest that the numbers required to justify ADSL-enabling an exchange are set too high; the registration process is deliberately obscure; BT want to give the impression of enthusiasm for wider roll-out but are in reality happy to keep it slow.
"I prefer the alternative conclusion - that at the top of BT there is a real commitment to "Broadband Britain", but a gap between the strategic intention and an understanding of what is needed to make it a reality," said Sir Young.
Campaigners have claimed that just 50 subscribers can make rural exchanges viable. Executives at other operators insist that their own business models are closer to these lower figures than BT's thresholds.
David Cleevely, chairman at analyst Analysys, which advises the government on broadband, commented: "The key issue is that at least the thresholds are now explicit and can be debated.
"Indeed, BT will be under pressure to justify thresholds area by area ... their appetite for risk is rather small."
Cleevely added that the government's goal was to make broadband available to all of Britain and that "bandwidth should be mentioned in the same breath as water, gas and electricity", in terms of importance to the economy.
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