Congestion Charge - BMDUBYA
Personally I think they should pay up:-)

news.bbc.co.uk/1/hi/england/2803699.stm
Congestion Charge - volvoman
One of the side benefits of this scheme may well turn out to be a much clearer idea of just how many unregistered or cloned cars are out there!
Congestion Charge - Armitage Shanks{P}
It seems to me to be a bit more than an "Operator error" if an ancient car with a one letter and two digit number plate can be mistaken for any car that is likely to be on the roads in Central London today! It would be fascinating to see the "images" that led them to issue the penalty notice but I am sure there will be some excuse to keep us uninformed, as usual!
Congestion Charge - DavidHM
Saw a Bentley today, the registration was something like 5V - one number and one letter. So if that paid its congestion charge (or at least the owner did) then why not Y99?

Alternatively Y99*** could be the first three letters of an otherwise illegible or obscured plate.
Congestion Charge - Armitage Shanks{P}
Because Y99 is a 80+ year old car that looks like a farm cart with a leather sofa stuck on it and tiller steering ie really ancient and not mistakeable for a 'normal' car as might be seen cruising Ken's ghetto!
 

Value my car