If the Thames Estuary even came close to fitting into into your category of being an "identified, and impossible to manage, safety risk" it would not be continually promoted by so many proper experts as a way forward. There is an excellent report that was published in the New Civil Engineer by Douglas Oakervee (a hugely respected engineer of HKG construction fame) and some key points from it are as follows:
"Therefore, this data indicates that although bird strikes are a real issue there are ways to overcome the problem without being aggressive towards the birds. Whilst much is written on how best to resolve the problem and should be reviewed in detail, I believe the issue should be addressed with the RSPB to find the right solution for the Thames Estuary which must be regarded as both unique and precious"
And goes on to say...
"MetroTidal in their studies have produced a map of the flight paths across the estuary and is included as Figure 20 below. If this is representative of the actual situation it would appear that the likely location is relatively free from bird movements"
There is also an interesting comparison of the number of bird strikes that LHR, LGW and STN currently suffer annually - interestingly LCY suffered none.
http://www.testrad.co.uk/aboutus/oakervee.html
You mean LCY reported none. It's not the same thing, as anyone who works in bird strike prevention knows. An airport which reports no bird strikes is 99 % of the time down to poor reporting (or occasionally lack of movements) or detection, rather than good bird control. There is sufficient research (I refer you to Horton and Milsom's work on the matter, and also the US based researcher whose name escapes me, the Transport Canada and FAA work (the FAA work was an add on to the US researcher's work) and even Tom Kelly in Ireland) to show that bird strike reports are very susceptible to reporting biases.
But anyway, I digress. I have to say, I don't know where Hansard got the data from, but as someone who analysed the raw data from those airports in those periods - that data is incorrect.
There are probably 20 people in the world who are qualified and experience enough to conduct the kind of safety assessment this proposal requires. I don't like to blow my own trumpet publicly - but I'm one of them. If you want to quote experts who worked on HKG - well quote me also.
The mere fact that someone is writing 'there are always ways to overcome the problem' shows they don't know what they are talking about. There aren't. That's why the The loss of the Hawk at RAF Valley was down to birds, and was completely unpreventable. You can do a lot to manage the situation, but as the authors of the safety assessment for the proposed Cliffe airport found, there are limits, when the area is crawling with birds.
If anyone thinks the area is free from bird movements, they're living in a dream world. What figure 20 shows is the main routes around the area. However, birds don't stick to those - they are more indicative of axes of movements rather than the actual flight paths. In fact, that figure bears more than a passing resemblance to the one produced by the Cliffe airport study, which, so far as I know was the most indepth study into bird movements around the area, where the flight routes were mapped to be indicative. In actual fact, the data from Cliffe showed birds in flight over the area pretty much the entire time - and that's one of the reasons why the authors rated the risk so high. You cannot stop birds flying.
In short, that assessment you reference has been produced by someone hoping it is correct. It is not a proper safety assessment. It relies on incorrect assumptions and incorrect data to arrive at the solution the report authors want, that it isn't a problem. They obviously haven't worked with any one with any expertise in the field and I suspect many of us would have strong reserverations about trying to say the scheme was safe. At best, we could benchmark it to existing conditions and compare and contrast predicted with existing.