Horrified to read this.
I don't want to hijack the thread but may I share my own similar experience?
On NYE 2013 me, my husband and daughter (14) we're trying to get to the Gary Barlow gig at Central Hall Westminster.
Many roads were closed, our taxi driver was clueless and he dropped us at Blackfriars Bridge and suggested we walk to the venue.
We walked along the embankment, as soon as the crowd got to the deepest point we formed a chain by holding hands (husband-daughter-me) and tried to get through the crowd.
As you can imagine, nobody wanted to let us through, people thought we were trying to get to the front for the best view. The police wouldn't / couldn't let us out and advised us to carry on pushing through the crowd 
It was absolutely rammed, people were packed in so tightly.
We got to a point where we were at a standstill, daughter was sandwiched between me and my husband.
Thank goodness, as someone put their hand up my dress and grabbed me in such an aggressive and forceful way. Had I not have been wearing 100 denier tights I am quite certain that they would have penetrated me.
To my mind there was definitely more than one or one pair of hands on me 
When I turned around to see if I could see who was behind me, all I saw was huge group of men.
I don't know how to say this politically correctly, but they weren't white and I'm pretty sure from their shouts and laughter that they weren't British.
I was shocked by what happened and relieved (that it wasn't my daughter that was attacked). I often wonder how many more people were assaulted by that group that night.
Thanks for reading, that's not a story I tell much IRL x