On a recent 221 bus journey from North Finchley to Mill Hill three boys let off a 'stink-bomb' which was very unpleasant.

That evening I had a severe bilious attack, caused by inhalation of this noxious gas.

I don't wish to be a spoilsport, and I'm sure the boys meant no harm, but were merely being mischievous.

However, I think they, their parents and the shopkeepers who sell these things should be more aware of the danger. I am 82 and am an insulin-dependent diabetes sufferer.

Ann Cocking

Bittacy Park Avenue, Mill Hill