Blood on the streets

If you want to know what effect any intervention in London would have, you need first to design the intervention (people on this thread are talking about a much bigger change than getting only the biggest trucks out of the city centre during the day) and then to ask the vehicle operators and their customers what they would do in order to comply with the intervention, either maintaining the current level of economic activity or reducing it in the face of such an intervention.
.

It's funny, this is exactly the kind of logic that the banks and the oil/gas sector use when they're trying to fight new regulation. Thus far, we seem still to have banks in the City and people are still investing in new production capacity in the North Sea. We might have lost a few trading shops to Switzerland and have not developed a couple of the smaller, more complex fields, but on the other hand we don't have the financial risks associated with potentially having to bail out the trading shops, and if an oil field isn't viable at over $100/bl maybe we would do better to deploy the cash elsewhere. Like energy efficiency.

Generally, when demand for a good or service is relatively inelastic, a slight increase in the marginal cost because of a heavier regulatory burden doesn't actually kill off the activity, although it may make the most marginal instances of its use economically unviable. In the context we're talking about, that most marginal use would be driving lorries around in central London that are loaded to well below their carrying capacity. Which most people here would think to be a good thing to lose. But the world wouldn't end, and it's cod-economic bullshit to pretend it would.