The thick fog which blanketed Heathrow last Christmas contributed to a dip in flight punctuality at major UK airports in the final three months of last year, it was announced today.

The number of scheduled airline flights on time in October-December 2006 was 68% compared with 73% in the same period in 2005, the Civil Aviation Authority (CAA) said.

The average delay for these scheduled flights rose from 15 minutes in the last three month of 2005 to 18 minutes in October-December last year.

Charter flight punctuality dipped from 69% of flights on time in the last three months of 2005 to 67% on time in October-December 2006.

The average charter delay rose from 23 minutes to 29 minutes.

The statistics related to flights in and out of 10 UK airports - Heathrow, Gatwick, Birmingham, Luton, Stansted, Manchester, Newcastle, Edinburgh, Glasgow and London City.

The CAA said delays between December 18 and 23 last year - when the effects of fog were most severe - contributed to about half of the fall in punctuality for scheduled airlines and all the decline for charter flights.

Among the top 75 destinations, 11 scheduled routes had on-time performances of less than 60%. These included New York, Dubai, Hong Kong and Los Angeles.