London  - British Telecom Friday issued a surprise profit warning, telling shareholders results for the quarter ending September would be slightly down on expectations.

It said its Global Services section, used by big multinational companies, had failed to meet its targets after cost-cutting measures took effect more slowly than expected.

All the company's other areas of operation had performed as expected or slightly better. BT's half-yearly results are due to be published on November 13.

The company's latest announcement sent the value of its shares slumping, losing a fifth of their value in the first hour and a half of trading Friday.

BT had already disappointed shareholders with its first-quarter results, which showed a 35-per-cent drop in profits to 607 million pounds (770 million dollars). (dpa)