We used to do this day in day out in London. If it is whitewash, the only way we got it off was grind the bricks. c@£t of a job.
If its normal paint, youll get it off with reasonable ease using a paintstripper. We used DCM based strippers, but refer to the other paintstripping post for legalities. You can still buy it, and you will need full ppe and mask everything up, watch out for splashes when your jetting it off, and the clean up is a bitch!