(This inaugurates a new column on filming on locations. Contributions welcomed.)

Suddenly, I feel a massive hand clutching my shoulder and I look around to see one of the city’s famed Bobbies towering over me. He looks seven feet tall in his black helmet.

“Excuse me, sir,” he said, taking his hand away now that he had my attention. “Do you have permission to film in the square?”

“Of course, officer,” say I, reaching into my camera bag for the requested document.

He glances at the permit then at me, eyes steady. This permit is out of date. It’s for Tuesday last, between 10 and 12 noon.

Today is Thursday 4 p.m.

I apologize, saying I thought the permit was legal during my entire week-long shoot in London.

He shakes his head. “You’ll have to get a new permit, sir. Permits are good for one time only.”

I knew the rules. I was hoping that no copper would spot me. I should have known better. Trafalgar has been the historic spot for some of London’s hottest demonstrations. It’s under surveillance around-the-clock, not only from Metropolitan Police but now “post-9-11” cameras mounted almost everywhere in the city.

He watches me as I pack up my equipment and walk over to a taxi rank.

It wasn’t the first time I had been stopped from shooting. A few years earlier I was shooting—also on a tripod—at the Changing of the Guard in the Horse Guards compound when a Bobby pulled me away and demanded I stop.

“Why?”

“It’s against the law,” he said.

As I removed the camera from the pod, I mumbled something, “Why don’t you stop all the tourists with their camcorders?”

He smiled. “They don’t have tripods.”

And that was the trouble. Use a hand-held camera, no problem. Set up your tripod—problem.

If you are making a serious film in London, my advice is to check into the British Tourist Board on arrival to get shooting OK’s.

When I was filming in London a few years ago, I had to get camera shoot permits at the Department of the Environment. Honest. Their offices are on the Thames embankment.

—Hal McClure