Overnight falls on the US stock market have helped to knock the FTSE-100 Index down by 36.3 points.
The Footsie is now standing at 5783.0 after technology and telecoms stocks came under pressure.
This was caused by a series of US profit warnings that wiped more than 2% . losing more than 2% of its value, dealers say.
The main fallers include Telewest Communications, down 4½p at 106¾p, telecoms equipment firm Spirent, off 8¾p at 212p and chip designer Arm Holdings, down 10¼p at 283¾p.
Vodafone is also suffering, off 3¼p at 168p, while BT slipped 7p at 443p as it prepares to close its right issue tomorrow.
Merger partners Halifax and Bank of Scotland both issued upbeat trading statements as they set a target date of September 10 for the creation of the new banking giant HBOS.
But their shares have failed to respond, with Halifax up just 2½p at 805p and Bank of Scotland down a penny at 805½p.
Two retailers - Courts and Harvey Nichols - have failed to impress the City with their results.
Courts is 11p cheaper at 345p after pre-tax profits took a dip on the back of tough trading conditions in the autumn.
Harvey Nichols is blaming falling tourist numbers for a tough start to its current financial year. Shares have fallen 9½p at 207½p.