This happened about a week ago and I'm still cringing and chastising myself. I'm usually fairly gobby when required but words failed me 
I was on fairly lengthy bus journey and got talking to an old lady (her words she was 71) we talked for ages about her dog that had died and were getting along very well.
A man got on a couple of stops before she got off and she starting making stage whisper comments along the lines of "likes of him shouldn't be allowed"
"they come over here and it's all paid for for them out of our money"
"They get given free cars" (this was on the bus!)
You get the picture, this poor guy (who I should add was wearing a very smart suit) was standing at the front of the packed bus so in full view of all the rows of seats and being as we were only a couple of rows back there's no way he couldn't hear.
I still cringe with shame for not calling her on it but I just sat there literally open mouthed in horror throughout the whole tirade and while she said bye and got off. She seemed oblivious to both my reaction and the auidible tuts (amplified by stunned silence)
I was fully aware that the battle of sexism still had many wars to win but confess I had no idea that people of colour living in a large multicultural city (Edinburgh) could still expect such blatant racism 
I wish there was some way I could go back and untie my tongue 