Over a period of years the UK CAA have been becoming increasingly concerned about the number of controlled airspace infringements. They decided to commission a project to analyse the reasons why. There is a good website with useful information here:
Fly On Track
This report is the recommendations of this project. Airspace, especially in the areas such at Heathrow/Gatwick, Manchester, Luton/Stansted, is complicated and requires enhanced navigational caution. Airspace infringements are not restricted to these areas, they occur in different places for different reasons and the research is looking at patterns of flight behaviour and other contributing factors in order to make any changes felt necessary.