Victim Support and the National Crime Agency has advice for people who are being threatened for money or with humiliation.
Lord Lester said he had been “treated despicably”.
James Froomberg had claimed he was asleep and denied sex assault.
Several teachers said 'upskirt' images had been taken of them in the workplace.
The Equality and Human Rights Commission called on the Government to introduce legislation stopping employers from ignoring complaints.
The actress said she has been left terrified about speaking up.
More than half of the women surveyed by the TUC say they have experienced workplace sexual harassment but the majority have not reported it.
Affleck was sued by two women for alleged sexual harassment in 2011 before the lawsuits were settled out of court.
"You are one of the silence breakers and we all owe you a debt of gratitude."
The French actress said in an open letter that the latest wave of sexual harassment allegations is fuelled by a "hatred of men".