Shares in software group Logica have fallen by sharply after the company said it expected sales growth to slow during the next six months.

The announcement from Logica, which has until now held out against the technology sector downturn, triggered a tech share sell-off in London.

Logica said it expects sales in its key mobile networks business to grow by 30% during the first half of next year, down from original forecasts of 40%.

The company, which makes software for mobile telephone text messaging, blamed cost-cutting by key mobile network operators such as Vodafone and BT.

Logica's own shares fell more sharply than any other in London on Thursday, closing 15% down at 705p.