I think that probably covers the main elements.
You'll be aware of the elements that are required for a successful screening program. Those include a population at risk that you can intervene with rather than just diagnosing someone earlier but not being able to change the course of their disease; we have that. There's having a test that is safe and accessible. We have that in the low-dose CT scan. You need to have an effective treatment; we have that. That's surgery, or in some cases radiotherapy for cancers caught at an early stage. The other element is that it needs to be affordable, which is—thankfully for me—your problem, not mine.
CT scans to screen the whole population would be probably unrealistic. The evidence to date is to go for the low-hanging fruit. We know that 85% of lung cancers are related to cigarette smoking, so we screen people who smoked heavily. That's where the benefits have been seen. If we can prove over the coming years that this is effective, affordable, and acceptable to the population and the public purse, then for sure, if there's good evidence, why couldn't we look to expand that to other groups?