It will probably be of scant consolation to Jude Hill, whose daughter’s friend was choking on a sweet while on a London to Brighton train, to say so, but it may be that their fellow passengers did not know how best to respond to such an emergency (Letters, May 17).

On a first aid course I attended some years ago, we learnt that the usual reaction of someone who finds themselves choking, whether at table or not, is to absent themselves from any company present.

In fact, they should be helped to bend over the back of a chair, or something similar, and to push, or “pump”, quite forcefully.

This sufficiently constricts the midriff to cause the offending object to be expelled.

The same effect can be achieved by encircling their waist with linked arms from behind and then repeatedly pulling back hard.

I can only regret that the opportunity to remind people of this helpful tip has resulted from such a distressing display of apparent indifference on the part of other rail travellers.

For those who live alone, the technique can usefully be likened to a line from Jailhouse Rock: “If you can’t find a partner, use a wooden chair.”

Steve Williams, Foxhill, Peacehaven