Seems that Luton is the worst UK airport for flight punctuality with departures from the Bedfordshire hub leaving on average 19.7 minutes late although there is not much in it with Birmingham,Teeside, Jersey, and Gatwick all above 18 minutes.
Looking at Luton today there are 17 departures from 5:55 to 6:30 and 44 to 08:00. There are also 13 arrivals between 07:00 and 08:00 making a total of 57 moments to 08:00 which is rather impressive at almost 1 movement every 2 minutes.