I know many of you hate the view from elsewhere but if you want to know what informs opinion the other side of the channel the real bugbear for many really is the lack of reciprocity (which was supposedly something that the UK agreed to).
Agreed to with whom, please?
Because, as far as I can see, there are no agreements between countries. There are agreements between individual countries and vaccine suppliers.
Production within the UK is owned by Astrazenaca UK. Which is a different entity from AZ AB, with whom the EU have their contracts. The EU does not, as I understand it, have any contracts with AZ UK. And the UK does not own any manufacturing capacity - like Europe, it simply has private companies who do within its borders - so I don't see how the UK could have contracted anything with the EU.
Please correct me if I'm wrong, but that's how I see the legal picture.
Companies in the UK do have contracts with Pfizer to supply lipids, which are essential for manufacture. And, it has been said up-thread, the sensors needed to confirm the cold chain of the finished vaccine.
Again, correct me if I'm wrong, but I don't think there's been any suggestion that the UK have blocked those exports.
It seems to me that UK-based companies are supplying what the EU ordered. And EU companies are doing likewise, within the restrictions of upscaling an unpredictable biological process. That is reciprocity. If the EU has an issue with its suppliers that is between them and those suppliers. It's only become an EU/UK dispute because the EU made it so.