As I'm currently seeing more of the Physio therapy department at my local hospital than my workplace I can't give a definite answer as to what exactly has happened .
Last year we handled more traffic than ever before , this year we know we have at least a 25% increase on that which we handled last year with no more staff to do it with ( although that is trying to be dealt with), several overloads happened last year all of which were extremely nasty and as they were shared around the unit and between various levels of experience could not be put down to the ATCOs involved but the sheer volume of traffic going through the sector. In each overload there were a large number of en route trainers.
It may surprise some to know who work either at units nearby Cardiff or have moved on that every hour we have a large influx of trainers going through the airspace, they are low and slow often taking up several Flight Levels. EXMOR it is common to have maybe 4 trainers at the same time whilst trying to deal with all the inbounds and outbounds from Cardiff, Bristol and Exeter.
It was decided to look at all procedures to see how we could better deal with them and ensure that the chances of overloads are reduced, the idea of flowing Trainers through the sector has been around for a long time, we could put this through Brussels of course and get them to put a flow restriction on or we could just at least try to ensure that we regulate the trainers at each Beacon at any time.
The airspace is controlled by just One ATCO, the same airspace at Manchester is controlled by several, so we decide we want to make sure the ATCO doesn't get overloaded this year, it is like any procedure fluid, should we gain more staffing and the responsibilities are shared then a new procedure can be looked at again.
Before people criticise perhaps they should check the facts, one person has only so much capacity.