It was a former ship’s captain who wrote the sailors’ hymn, Eternal Father, strong to save, the anthem of the Royal Navy, and beloved of seafarers everywhere.

John Newton, who was born in Wapping, had been captain of a slave ship, transporting African men and women from their homes across the Atlantic to be sold for work in plantations.

As if being involved in the slave trade was not bad enough, Newton saw slaves thrown overboard to drown, for reasons of overcrowding or sickness, and was later wracked with guilt at what he had done. Having sought forgiveness, he wrote the hymn Amazing Grace, how sweet the sound that saved a wretch like me in thankfulness that even a man like him could be saved from his past.

Newton had learned that all men and women are to be respected as fellow human beings. He knew as a former seafarer that, when in trouble at sea, everyone is worthy of being saved.

Happily, that principle is now enshrined in international law, which places a duty on the master of a ship ‘to render assistance to any person found at sea in danger’.

For that reason, I was shocked to read a column by a well-known person in a national tabloid in which she called migrants adrift in the Mediterranean ‘cockroaches’. She said that she would prefer to send gunships to desperate people rather than rescue ships. All this at a time when we are hearing of hundreds of people drowning in a sea that many of us think of as a holiday destination. The use of the word ‘cockroaches’ is especially worrying. I remember Rwanda’s dreadful genocide being made possible by inflammatory rhetoric in which people of a particular tribe were dehumanised as ‘cockroaches’. Let us be clear: All people matter, whatever their background, and the answers to the world’s problems do not lie in demonising or dehumanising particular groups.

We can have our differences, certainly, but – whatever else - let’s treat each other as fellow human beings, whether at sea or not. More from Elwin