British Transport Police (BTP) are investigating the "reckless vandalism", which follows a number of previous attacks on the same line. They said "This was a reckless act of vandalism and I cannot emphasise strongly enough the dangers associated with this type of crime."
John F who gave me the heads up to this story said "I just cannot fathom what goes through someone's mind that they think it's okay to vandalise a moving train as it's passing by them - especially by doing something so dangerous as throwing bricks at it!"
Apparently the attack went on for two hours! I find it amazing that the police weren't on the scene much faster to stop this.
In this case I really have sympathy for the train drivers' union ASLEF. Steve Grant, London district secretary, said: "This was a very serious attack. We could easily have had passengers or staff seriously injured or even killed.
"Security must be stepped up. If not I will order our members to withdraw their services on safety grounds for passengers and their own sakes."