BT has delayed the launch of what it had hoped would be the world's first commercial 3G (third generation) mobile network by at least three months.

Blame falls at NEC's door. NEC makes the handsets for the BT 3G project, and the delay is due to a software fault with those handsets, a company spokesman said Monday.

"We've decided to push back the launch of the 3G network until the end of summer or early autumn," said BT spokesman Simon Gordon.

The launch of the 3G services on the Isle of Man through its wholly owned subsidiary Manx Telecom had been scheduled for 31 May.

A bug in the handset software is causing the phones to crash, Gordon explained.

"There is a problem that occurs between the base station and the handsets which NEC couldn't fix before the launch at the end of May," Gordon said.

Specifically, when a mobile phone user moves from one base station to another, the connection is cut off. BT and NEC are working to solve the problem "as quickly as possible", Gordon said.

Last month, Japan's largest cellular telecommunication carrier, NTT DoCoMo, pushed back the launch of its 3G services until October because of similar problems with NEC technology.

According to various reports published in the UK, NEC dragged its feet in fixing the BT handset bug by the end of May because of intense pressure from DoCoMo, which is leaning on NEC to make sure the Japanese company wins the competition to launch the first commercial European 3G service. It is a charge Gordon strongly denied.

"Those reports are not correct and there is no spat between BT and NEC," Gordon said.

But when BT announced last week that it had, with Nokia, successfully completed its first 3G trial, the company was still insistent it was on schedule to launch its Isle of Man services at the end of May.

"We only found out recently that the bug could not be fixed in time for the launch," Gordon said. "We will still be the first company to launch 3G in Europe, possibly the first in the world to launch 3G."