Fewer than one in six women sexually assaulted by rape or penetration reported it to the police, new figures have revealed.
Four in ten of them were too embarrassed to formally report the offence, while 38 per cent did not think the police could help and a third feared that the experience would be humiliating.
The annual crime survey by the Office for National Statistics (ONS) found that 1.6 million adults had experienced sexual assault by rape or penetration, including attempts, since the age of 16.
The survey of adults in England and Wales suggests that one in 40 women aged between 16 and 24 are raped or assaulted by penetration, including attempts, every year.
In the 12 months to March last year, 0.8 per cent of all women aged over 16 said that they were victims of these crimes, compared to 0.1 per cent of men.
Over the same period, 773,000 adults said they were victims of any type of sexual assault. There were almost four times as many female victims at 618,000, compared with 155,000 men.
A total of 162,936 sexual offences were recorded by police in England and Wales in the year, a drop of 0.7 per cent compared with the previous year, the ONS said.
An estimated 16 per cent of women aged 16 to 59 who had been victims of sexual assault by rape or penetration since the age of 16 had reported it to the police. This compares with an estimated 19 per cent of male victims.
Campaigners said that the figures laid bare the lack of confidence women had in the criminal justice system when it came to reporting male violence.
Earlier this week the government announced that all police forces would start recording offences that are motivated by misogyny as hate crimes after coming under mounting pressure to boost protections for women victims after the death of Sarah Everard.
Diana Fawcett, chief executive of the charity Victim Support, said that much more needed to be done to encourage victims to report incidents.
She said: “Sexual offences have a devastating and long-lasting impact on people’s lives and it is vital that victims who come forward are treated with respect and given high-quality support every step of the way through the criminal justice system, from speaking to the police to giving evidence in court, in order to help them rebuild their lives.
“Sadly, for many women, this is not often the experience they have. Last Saturday’s reaction by the police to women at Clapham Common is an instance of the wrong message being sent out when now, more than ever, we need to challenge male violence against women.
“Much more needs to be done to encourage victims, particularly female survivors of sexual violence, to report incidents and ensuring we shift from the ‘victim-blaming’ culture which is widespread in sexual offences cases.”