He was probably in his early 20s, heading to the city centre aboard the Thornhill park-and-ride shuttle, a large musical instrument case wedged between his legs.

Sitting next to him on the bus's back seat was a 15-year-old boy with learning difficulties. He tried to engage the man in conversation, first saying: "Hello, my name is Harry," then telling him excitedly that he and mum, who was alongside, were going shopping. These simple pleasantries went ignored.

After a short silence, the teenager pointed to the case. He said: "I'd like to play a guitar."

"It's not a guitar - it's a cello. Can't you tell the difference?" the other snapped, before pointedly turning his back on the crestfallen lad and staring out of the window.

The woman, hurt by the unkind response and the unnecessary snub, held her son's hand with motherly reassurance.

Other people, of a less tolerant nature, might have considered grabbing the musician by the throat.

Such a possibility seemed my fate when the flustered middle-aged couple rounded the corner into Great Clarendon Street.

I was making notes on a small black-bound pad; the short-term memory isn't what it was.

"We are only a few minutes over time," the woman explained. "We were held up. It wasn't our fault."

"We were sure an hour would be enough time for our business," put in the man, in a plea for understanding.

I took it they were talking about waiting regulations and feared they were being held liable for some parking transgression. But what had it to do with me?

Then it dawned. I was all in black - trousers, shirt and jacket. It seemed I was being mistaken for a traffic warden (universally known from this week by the crackpot title of civil enforcement officer). Should I put them wise?

Perhaps it was the wish not to embarrass - or possibly latent juvenile devilment - but I closed my pad and, while neither claiming to be, nor denying that I was a warden (or a civil enforcement officer), politely suggested they drove off safely at their earliest convenience.

They were about to thank me, but this would have been too much. Raising a hand in feigned protest, I walked off with the measured pace that befits the genuine article.

The question is: should I charge the council a fee for this impromptu customer relations work? Maybe not.

An excavator was perched precariously half way up (or, if you like, midway down) the Castle Mound. It was doing what it does best - digging dirt and dumping it on a lower point, all part of the restoration work on this historic site.

While marvelling at the skill and daring of the driver, operating at a dodgy angle of 45 degrees, I wondered how someone had managed to put the machine high above New Road in the first place.