Ratings agency Fitch has said the updated fiscal and economic projections from the UK's Office for Budget Responsibility mark a "significant deterioration" in prospects.
The loss of France's AAA-rating would be a worse scenario for the global economy than the downgrade of the US, said Ignis chief economist Stuart Thomson.
Managers fear France could be the next European nation in line for a downgrade as it steps in to support beleaguered bank Dexia.
Standard & Poor's has maintained its AAA long-term credit rating for the UK and said the outlook remains stable, while warning GDP will be lower than forecast for the next three years.
Hugh Young, manager of Aberdeen New Dawn Investment Trust, examines how Asia's economies have transcended worldwide chaos.
Threadneedle's Philip Dicken says a bleak European outlook is is cause for caution, but not excessive negativity.