Photographs depicting men and women who have been raped by soldiers are the focus of a powerful campaign by the Ministry of Defence (MoD) warning service personnel that consent is always required before they have sex.

The offensive against rape will see posters with the slogan ‘Don’t kid yourself! Without consent it’s RAPE’ displayed in army barracks and training centres across the country in the coming weeks.

A poster from the MoD's anti-rape campaign

It has been instigated by General Sir Nick Carter, the head of the army, amid concern over sexual offending in the military, and is the first time the armed forces have launched a campaign aimed at rape and sexual assault.

The posters, developed in consultation with Stonewall and Rape Crisis, portray a number of scenarios ranging from a female soldier raped by her colleagues to a male rape victim. They are captioned with comments indicating stereotypical attitudes held by some soldiers. One of the posters, featuring a man sat on the floor, trousers around his knees and his head in his hands, with a smirking man in the foreground, has the words: “He’s gay, he would have been gagging for it.” Another, showing a picture of a woman wearing a short skirt, says: “... she was asking for it.”

Service personnel are being warned that someone being passive during sex does not constitute consent, nor does how someone dresses or behaves. Consent has to be free and informed, so someone who is sleeping or drunk cannot give it. Differences in rank do not give individuals any right to have sex, and it does not matter if offenders think they are just having a laugh, for sex without consent is rape, say defence officials.

The new initiative will feature in the August issue of the British Army’s Soldier magazine. In a statement, an Army spokesperson said: “The Consent Campaign, which has been endorsed by Rape Crisis and Stonewall, is the latest in a number of internal initiatives that the Army has launched to ensure all of its employees act lawfully and treat each other in a way that is consistent with our values and standards.”

This comes after an MoD report released on 20 July revealed that almost half of service personnel believe sexual harassment is a problem in the Army. It also found that nearly four out of 10 female soldiers had been subjected to comments of a sexual nature in the past year, in what General Sir Nick Carter has described as “totally unacceptable” and a “problem of culture.”

“The imagery and messaging are bold, hard-hitting and, most importantly, really clear about consent,” said Katie Russell, spokeswoman for Rape Crisis England and Wales.

The report into sexual harassment in the British Army warns: “Although the policy within the Army is clear on what behaviours are acceptable, this is clearly not resonating with some service personnel. There is a possibility that some individuals simply do not understand that they are doing something wrong.”

There have been more than 400 cases of rape or sexual assault in the military in the past five years, according to MoD data. But these do not represent to full scale of the problem, as they do not include cases investigated by civilian police forces.

Sometimes senior officers fail to refer sexual offences to the Royal Military Police, warned a report by Her Majesty’s Inspectorate of Constabularies earlier this month.

And the lack of comprehensive and reliable statistics on the number of allegations of sexual assault and rape made by and against service personnel remains a concern, according to Liberty.

The new campaign to reduce levels of sexual offending in the armed forces was welcomed by campaigners last night.

“The imagery and messaging are bold, hard-hitting and, most importantly, really clear about consent,” said Katie Russell, spokeswoman for Rape Crisis England and Wales.