The uniformed policeman stood in the road next to his motorbike and pointed sternly at me to pull over. “Census” said the blue sign propped on the pavement. I pulled over. A woman in a reflective jacket stuck her head through the window and thrust a card at me. “Thank you for taking the time to provide Transport for London with this important information,” it read. Eh? Transport for London? What information? Since when do the police pull you over so you can have a chat with TfL?

The answer, it turns out, is since TfL decided it needed help with a little light information-gathering. Nothing serious, you understand: just things like where you're going and why. Things that are categorically none of its business but which will, it says, “help us better understand travel patterns in London”.

According to a spokesperson for TfL, the police are present simply to make sure the traffic flows smoothly. But my journey wasn't being smoothed, it was being forcibly interrupted. The policeman wasn't expediting me, he was directing me to pull over and I am legally required to comply. TfL's own handouts tell it like it is: “Stopping vehicles in this way is the only effective way of establishing the volume and types of journeys being made.” I bet it is.

TfL later said, as if this made it better, that it only uses off-duty policemen. But why are off-duty policemen impersonating on-duty ones? And to assist TfL?

This summer TfL will be operating 230 “roadside surveys” across Central and North London, which will all require the presence of a police officer, who may or may not be on duty - but who can tell the difference? You might think that the police would have better things to do. Investigate stabbings, say. Solve a few burglaries. Apparently not.

When I queried this, the surveyor got stroppy. “The police have the authority to pull you over,” she snapped. True, but that's not the point. When pushed, she admitted that I didn't have to answer their questions (so I didn't), but how many people are going to make a fuss?

How many are going to feel cowed, obediently answer yes and no, and end up as a statistic backing some TfL “multi-modal transport” proposal? What wouldn't pollsters and market researchers give to have the might of the police at their disposal?

If Transport for London wants to ask me something, it can call me, or write to me, and I may or may not tell it; using the police in a crude attempt to force me is disgraceful. As for the police, whose power to stop people from going about their lawful business is an awesome one, they should be ashamed of themselves for using it to help TfL to tick boxes. And if they really are off-duty, they've got some explaining to do.

Hilary Rose is a Times feature writer

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