Why does the UK have 10x more swine flu cases than any other EU country?

I came across this map at The Guardian’s website about worldwide numbers of swine flu cases. I write this post from Belgium, currently at less than 200 cases, and more or less free of the swine flu paranoia seen in the UK. But why has the UK been so hard hit? The UK currently has 10000 cases, 10x the next largest number of cases in an EU country – 1000 cases in Spain.

This map from the BBC details the worldwide spread, while the one at the bottom of the page shows the spread across the UK.

So what’s causing this? On Twitter, in discussion with @euromarianne, @markpack, @helenavelikaja and @itnorris, there are the following theories:

1. The ‘London Heathrow’ effect – that the UK is a hub for international travel, also shown through the Youtube video above. However the regional spread of the disease – i.e. right across the UK would seem to disprove this, as would the fact that Spain started to have cases before the UK did, but developed far slower. Germany in total would also have the same sort of numbers of transatlantic flights as the UK but has had only 700 cases.
2. The UK does not screen people at its airports as effectively as other places do.
3. The centralised nature of the NHS means the UK can more effectively total up the number of cases.
4. That there’s something specific about the immune systems of the British population, having never been exposed to Spanish flu.
5. That the British have bad personal hygiene…?

Anyway, whichever way it’s rather intriguing!