T-Mobile has been ordered by a judge to route calls to VoIP operator, Truphone - but it's only an interim ruling and isn't on the best terms.

Last month, T-Mobile blocked calls from its subscribers to the 079788 range of mobile numbers that Truphone owns, after they failed to agree on the "termination fee" T-Mobile would pay to Truphone to terminate calls.

The dispute is over a range of numbers that Truphone is planning to use for a service it will be launching in the next few weeks, based on VoIP calls to dual-mode handsets using Wi-Fi. It is currently running a beta test service using the 07624 range of numbers, rented from Manx Telecom - a trial which T-Mobile is happy to route to.

Truphone asked the court for an injunction forcing T-Mobile to activate its numbers saying it could not launch its service otherwise, given T-Mobile's 20-25 percent share of the UK's mobile market. The High Court of Justice ruled that Truphone has a case, so T-Mobile has been instructed to route calls to the Truphone numbers from Monday 23 July, while the case is being heard.

T-Mobile and Truphone have argued over the price T-Mobile will pay to Truphone for terminating calls, and the ruling only instructs T-Mobile to pay 0.21p a minute which it offered. Truphone wants 6p a minute, and describes T-Mobile's offer as "punitive", but appears to be ready to accept it for now, possibly with a view to raising a dispute on the actual fee through Ofcom.

It's a small victory then, but one which will lead to a bitter trial, since the two providers' positions are so far apart that one appears to have lied about the negotiations so far (read our analysis T-Mobile presses the legal red button). It could also signal an end to the stand-off between VoIP providers and traditional operators.

"Basically, T-Mobile's short-term hissy fit has long term ramifications," says dean Bubley of Disruptive Analysis. "T-Mobile UK has just pressed the big red button without thinking of the longer-term issues."