On 09/05/2019 19:11, Simon Jester wrote:
On Sunday, May 5, 2019 at 3:36:18 PM UTC+1, MrCheerful wrote:

or may be about to do.

Bai Jove! I think he's got. 'About to do' is the key.

So long as the hooter is doing whatever is necessary to reduce the danger.

I can only remember two occasions of witnessing correct use of the horn.

1) I was on foot in Barcelona waiting to cross a dual carriageway. The
hooter was in the lh lane overlapping another vehicle in the right hand
lane. The vehicle in the rh lane was drifting into the space the hooter
was already occupying. To distinguish from the situation of a vehicle
drifting into the space the hooter wanted to occupy.

2) I was cycling in France and a lorry was approaching from behind. The
driver hooted when he was 5 or more seconds away. The key is that if I
had not already seen the lorry, he did it in plenty of TIME for me to
prepare. Emphasis on the word time: if hooting is intended to be a
warning it can serve no possible purpose (and more likely to be counter
productive) when done at point blank range. Distance also attenuates the
noise to below a physically harmful level.