Punctuality at UK airports deteriorated sharply this summer, according to latest Civil Aviation Authority figures, with Gatwick and Luton performing worst.

Two out of five scheduled flights at Gatwick were delayed and one in three at Luton. The length of delays also increased – by an average nine minutes at Gatwick and seven minutes at Luton.

The figures for July, August and September show 72% of scheduled flights across the 10 principal UK airports departed on time, compared with 80% a year ago, while delays averaged 16 minutes –four minutes worse than in summer 2009.

Punctuality at Heathrow declined by nine percentage points to 71%- a fact partly explained by a significant increase in traffic on a year ago. However, Stansted – where traffic has fallen for the past two years – also saw punctuality decline by six percentage points to 72%.

Charter flights fared worse, with only 63% on time and delays averaging 30 minutes.