The short term danger is that mass imports flood the air with unsuited drones and stack the odds against preserving usefull genes from stocks not artificially propagated in large numbers.
Our aim should be passing on bio diversity to our successors, and to my mind, in beekeeping terms this can be achieved by opposing the agenda of those who would seek to flood the country with imports for short term commercial gain.
Yes we do export queen bees to the UK, yes we do sell them - we are not a charity. We make a living from breeding and selling queen bees.
Unfortunately your post above does not hold up when we look at the figures.
Year Number of queen bees imported
2014 9678
2013 8625
2012 7977
2011 4163
2010 7291
(Data from FERA)
If we say that on average about 8,000 queen bees a year are imported. IF they are all introduced successfully, something I doubt very much, and that each and every queen holds up for two years, we can see that at most there are 16,000 imported queen bees at any time in England and Wales. What is the total number of colonies? I have been told it is around 250,000. So do the calculation: It is about 6,5%.
So, where do you get the idea that the imported queens are flooding the air with undesirable genes? I say that the imported, don't forget it is selected material, is at a severe disadvantage in the mating area, something in the region of 12:1 against.
Re: Danish Buckfast material: I too have been very disappointed with some of these - some breeders' material is OK. Had I had my first experience with "Buckfast" bees from a certain source I would probably have not had anything to do with them. Luckily, my first experience was with some of the last Buckfast queens to have been exported from the USA to the UK in 1986. This really showed what bees can do and I have never looked back since.
You mention biodiversity, actually the UK had a genetic treasure house of genetic diversity at Buckfast, which was taken from the UK to other European countries, thank God, whilst the material at the Abbey was just left to die out.