The benchmark FTSE 100 index was 72.43 points or 1.35 per cent lower at 5,290.51 points at 8:32 am.
The election of a right-wing government in yesterday's Spanish election failed to impress the markets in the absence of any details of new Prime Minister Mariano Rajoy's budget plans.
Another factor for investors was a statement by Moody's Investors Service that a rise in the borrowing rate on French debt bonds and possibly slowing growth could have a negative effect on France's top AAA credit rating, though not immediately.
"It's a brand new week but the same old concerns hover over financial markets," said Tim Waterer, senior foreign exchange dealer at CMC Markets in Sydney.
"Debt debacles on both sides of the Atlantic continue to halt any potential uprising of brighter sentiment from traders."
The European Commission will publish legislative proposals for common eurozone bonds on Wednesday in the latest bid to contain the debt crisis, which has threatened to plunge the world economy into recession.
The financial sector took the brunt of the losses on the London Stock Exchange. Stockbroker Hargreaves Lansdowne dropped 4.16 per cent to 456 pence, fund manager Resolution sank 3.05 per cent to 241.30 pence and Royal Bank of Scotland shed 2.28 per cent to 20.10 pence..
Essar Energy was among the few gainers, adding 1.44 per cent to 246.50 pence.
On Tuesday, pubs group Mitchells & Butler is a scheduled to release full year results, while banknote printer De La Rue will issue interim figures.
United Utilities and restaurant group Compass will announce their latest results on Wednesday, followed on Thursday by travel company Thomas Cook and electronics specialist Dixons Retailer. Water company Severn Trent will publish interim profit details on Friday.
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