For those people doubting whether lasers are powerful enough to do you damage, it is possible to buy 3-5W lasers over the web and there is very little to stop them being imported into the UK or elsewhere. The limit here is 1mW (some countries allow 5mW) but the problem is quality at build. Just because it says 1mW on the tin does not mean it only produces 1mW - a pointer tested after it caused a permanent retinal burn to a child came in at 70mW. A 5W laser will be visible from 30+ nautical miles.
As for injury or otherwise, Fahd Quhill, the consultant ophthalmologist who wrote the article referred to in Tourist's post, has photographs of the retina of the pilot injured at LHR which show a clear laser burn. He believes the pilot was telling the truth about how he came to be injured and I don't understand why anyone would doubt him either.
For reference, the police will treat laser dazzle as an injury, albeit a temporary one, which makes the crime ABH. A permanent injury would be classed as GBH. Regardless, the laser attack was an offence under the ANO. The other thing people might want to know about laser injuries is that the disruption to vision will be immediate but can get worse in the following minutes, and it can also be some time before it becomes apparent the effects of (eg) dazzle are taking longer to fade (individuals differ in their response). The same is true of pain/discomfort from an eye injury. And if you have ever had an eye injury you will know that it is very distracting.
I would have made the same decision as the VAA captain - but then I am sat in my armchair with plenty of hindsight and both eyes working.