I agree with LTN Phobia and others that this is indeed serious (though I think 10 years would be very excessive). The captain did the right thing in diverting (isn't this standard procedure?).

I like the idea that he could be forced to compensate BA in full for the expense caused (quite right!).

He should never have taken what he took and drank alcohol all together, so for me this is not really a defence.

It's usually so calm and serene aboard the LCY flight. I can imagine that this would've been a big surprise for his fellow pax.

Thanks to LTN Phobia for clarifying the title (in fact the article I posted doesn't say when the incident happened. RTE news is not exactly the best of sources, but I couldn't find the story elsewhere).