'LOOK Mum! Bob the Builder's hat!" The four-year-old boy pointed excitedly at the unmistakable yellow headgear perched on a junction box outside the Waterman's Arms on Osney Island.

The hat didn't have that abandoned appearance and the boy clearly expected the fix-it man to appear any minute. Meanwhile, his young mother was struggling with his little sister who had recently acquired walking skills and was intent on practising these across the surface of the river to reach a passing duck.

"Leave the hat alone," she called over her shoulder. "Whoever left it there will be back soon."

"But it's Bob's," the lad insisted. "Someone might steal it. Let's look after it."

The idea was rejected, mum's pained expression suggesting she had enough to handle without looking after any hat - even if it was Bob the Builder's.

The three headed quickly towards Botley Road - the small boy anxiously glancing back at the lonely yellow helmet.

A LARGER-than-usual mid-morning crowd was in Market Street. There were bright lights, cameras and a production staff army. All became clear with the appearance of the slim, six-foot-six frame of actor Laurence Fox, alias DS Hathaway. Another instalment of Lewis, spin-off from the unforgettable Morse series, was being made.

Laurence, an unusually tall member of that otherwise vertically challenged, yet speedily expanding Fox acting dynasty, led by father James and uncle Edward, was having trouble with his mobile phone (not in the script). Meanwhile production staff were trying to persuade customers (also not in the script) to leave the Market Street cycle sales and repair shop, which was being used on the set.

A notice had been posted announcing the shop was closed for the day. But cyclists need bikes. Business, as well as the show, must go on.

An imitation police car bore a large stick-on logo that read Oxfordshire Police'. It sat at an untidy angle. The ghost of the ever-immaculate and stickler for detail, David Holdsworth, last man to head the old county force in the late 1960s, would have haunted whoever was responsible.

Fortunately someone spotted the offending board. It was straightened and haunting was avoided.

Filming was short and sweet. DS Hathaway' left the shop, accompanied by a second man and a police driver.

The vehicle moved 20 yards towards Cornmarket Street . . .

"Cut!" yelled a voice.

"That was a load of nothing," said an elderly man in a vivid blue jacket, whose hopes of stardom, even as background fodder, had been dashed.

AROUND the corner in Turl Street, an early arrival for the new term was with her parents outside the well-known University outfitters. "Look, £2 discount on college scarves - down to £22,99," she said.

"Two pounds," said father resignedly. "What a difference that will make."

A sentiment certain to be echoed a thousand fold over the next few days.

ON Osney Island, the yellow hat was still there, four hours later. Clearly Bob had not shown up. Would the little boy manage to ignite mum's concern for its fate when they returned?