Alcohol play a major role in many sex attacks over the Christmas period
Women heading out for Christmas drinks have been warned by police not to make themselves easy prey for rapists.
Senior officers in England and Wales warned of the risks as the Association of Chief Police Officers (Acpo) launched a campaign to raise awareness.
Poster, radio and TV advertisements will urge women to "let your hair down, not your guard", while warning men, "Rape: short word, long sentence."
Many forces record an increase in sex attacks over the festive period.
It comes as thousands of people head to pubs, bars and clubs.
The Acpo campaign was launched in Manchester where it is thought that alcohol plays a part in two thirds of all rape cases.
In the city there has been a rise in reported cases of rape over December and January in recent years.
The police campaign aims to raise awareness of a number of steps women can take to protect themselves and tells men of the need to seek consent for sex.
Cheshire Chief Constable Dave Whatton, the national lead on tackling rape, said alcohol tended to be a factor in a large number of rapes.
He said: "Ultimately we want to prevent rape from occurring in the first place, by arming potential victims with key advice on how to keep themselves safe.
"But we are also aware of the sad reality that many victims of rape remain silent."
Chief Constable Whatton urged victims to come forward and report attacks, pointing out that there were specialist agencies available to provide support.
He said: "The police service has been working hard to improve our own response to rape victims to ensure that by working with them and support agencies we can build the best possible case to bring offenders to justice."
Meanwhile, Fay Maxted of the Survivors Trust said the support group was "pleased that the police campaign includes details of a telephone helpline and information on where victims can find specialist services to access support".
Tackling rape remains a difficult issue for senior officers who are struggling to drive up a conviction rate of 6.5%.
And last week the government's "victims' champion" Sara Payne said women who had been drinking or came from poorer areas were not always taken seriously by police.
The campaigner's report said some police sometimes wrongly treat rape allegations with scepticism because of "poor attitudes" towards particular types of victims.
Last Thursday the head of the Metropolitan Police, Sir Paul Stephenson, said reported rape in London had risen by 25%.
A government review, led by Baroness Stern, is currently examining how to improve the treatment of rape victims and raise the conviction rate.