Well, the thing is that, the congestion charges, they were introduced first as a trial, so they were introduced in January and then abolished again at the end of July, followed by a referendum, and then they were reintroduced again in 2007, which of course was a wonderful scientific opportunity.
Le fait est que cette taxe était un essai, et qu'elle a été mise en place en Janvier et abolie fin Juillet, suivie d'un referendum, et à nouveau remise en place en 2007, ce qui a servi d'experience scientifique.