9.30 in Okehampton Town Centre, and it is not busy. I am standing opposite the pedestrian crossing, just up (or is it down) from the entrance to Red Lion Yard, between it and the flower stall. There’s a yellow plastic bag at my feet, and I am wishing that I was wearing something a little warmer than a T-shirt, fleece and scarf. I can see the church clock. It is not moving very quickly.

I am holding a collection tin, although these days they are yellow plastic. I emailed one of the girls earlier in the week, and told her that Caroline and I were going to sell flags in Okehampton on Saturday morning. Yesterday evening she told me that she had had a vision of the two of us wrestling with flags and wondering how we would sell them, and, rather more, why anyone would want to buy one. Only when I told her that for my generation, today’s stickers were, when we were children, paper flags, attached with a pin – ‘flags’ – did she understand.

As I told her, I recalled, aged 12, standing in the Square in Wallingford, selling flags for the Lifeboats, a tray of flags round my neck, and the lifeboat shaped collecting tin on a red string. My mother organised two collections, a house to house collection for Imperial Cancer Campaign – I used to go with her up Wilding Road (one of the longest in Wallingford, or at least to a small boy it seemed that) – and the other for the Lifeboats, which despite being some 100 miles from the nearest sea was always well supported. You don’t need to live next to the sea to feel the call of a seafaring heritage!

But back to Okehampton on a cold, grey Saturday morning. What struck me most was my invisibility to at least half of the passers by. Rattling the tin is not allowed, and so the next best thing is a sturdy good morning, then catch the eye, and smile. But for many, hurrying by, I simply didn’t exist – they looked right through me. It was disconcerting and, in a very small way, I felt what I am sure many Big Issue sellers feel – a nuisance, someone who if you ignore you can pretend isn’t there.

And yet for every two or three persons who scurried by, head down or consciously avoiding me, there was one who replied to the good morning, fumbling for change, apologising that it wasn’t very much, engaging in small talk – or like the couple in their late 60s who told me that the CAB had been their lifeline. That’s why it is worth doing it.

The CAB has done a brilliant job in Okehampton this year, and they do it every year. I may be a little partisan – Caroline works for them – but an hour on the street on a Saturday morning is all you need to know this.