Could be an easy way to get up motorists noses and increase accidents.
It works on the continent because they have a cycling culture and cyclists are appreciated. In London loads of cyclists break the traffic rules to rile motorists so having special permission to go the wrong way down a one way road could be something else to add to an angry motorists list. I still believe that you need to encourage a more cycling friendly culture, which will take time, as that would improve matters with existing traffic rules - so long as people obey them.
Hey, why put some effort in to it when you could try a quick fix. I'm surprised the CTC are behind it but then they're going on the basis that people obey the rules of the road.