BT is facing legal action over its decision to block premium-rate lines suspected of being used by rogue dialler companies to rip off punters and rack up huge phone bills.

Birmingham-based Opera Telecom is suing BT for blocking access to lines Opera leases to adult content outfit Netcollex and is seeking compensation for lost revenues.

BT says it will "vigorously defend" the action, which is due to be heard in the High Court on Friday.

In June last year BT responded to mounting concerns about rogue dialler software - which secretly changes a computer's settings to call a premium rate phone line instead of its usual ISP number - and began "proactively blocking calls to these numbers.

Late last week The Register learned that the UK's giant telco had abandoned its "block now ask questions later" policy. Now it's emerged that it took the action because of the threat of legal action.

A spokesman for BT told is: "We will vigorously defend the claim by Opera Telecommunications in respect of BT's action to suspend the premium rate number operated by Netcollex."

No one at Birmingham-based Opera Telecom was prepared to comment on the case. ®

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