IT was my favourite kind of letter, the kind that is folded and conceals a cheque inside.

The cheque, it quickly emerged yesterday, had been made out to The Big Issue. But the letter itself was thought-provoking.

The reader who sent it does not want to be named - I rang her at her home to ask - but with her permission her letter is reprinted here.

"After reading your article (on The Big Issue) in the Herald (on Friday)," it said, "I have been feeling a little ashamed.

"On Friday I was walking down Buchanan Street ... when a young man asked me if I would like to buy The Big Issue. I replied that 'I was a pensioner and could not afford it'.

"I usually buy a copy when in town but on this occasion was in a hurry to catch a bus to Fife, was carrying a small case and another bag, and it was too much of a hassle for me to try to find my purse - that really was the main reason.

"I had also come from the west end by train and all in all was a little stressed.

"I did think, however, that this young man looked very smart and wondered how on earth he was selling the Big Issue. I decided to give him something for a cup of coffee on the way back up Buchanan Street and ask about his situation.

"However, he was nowhere to be seen, and it troubled me greatly.

"I am enclosing a small cheque for The Big Issue as your article really affected me and made me realise how fortunate those of us are who have a home and family. Many thanks, yours sincerely ..."

The initial story had been about "guest vendors" - writers, chief executives and other notables - who sold the magazine for an hour last Thursday.

Some of them noted that many passers-by had been rude to them. "People," said one, "have to be more aware of what the sellers endure every day in order to make what is a very nominal amount of money."

It is easy to brush past the magazine's everyday vendors on the streets, especially if you're in a throng of passers-by.

Seeing hundreds of potential customers walk past you each day without even the slightest acknowledgement must be hard to take. I try to do my bit by buying the magazine; the reader's letter is a reminder that it really isn't that much of an effort to do something extra.

Needless to say, the cheque has been forwarded to the Big Issue. To the nameless reader: thank you.