Police are dealing with their largest ever volume of revenge porn cases, with victims ranging from 11-year-olds to pensioners, a Press Association investigation has found.

Forces have seen a marked rise in allegations since the Crown Prosecution Service (CPS) issued new guidelines on dealing with the cruel craze back in October.

Revenge porn, which involves sharing explicit or sexual images without the subject's consent, has been brought into sharp focus following a series of high-profile cases including pop stars Rihanna and Tulisa Contostavlos.

Latest details obtained from police forces in England and Wales show the majority of criminal allegations featuring revenge porn involved victims aged under 30, with eight female complainants for every one male, while the overwhelming number of cases involved former partners.

Campaigners have welcomed the statistics as an indicator revenge porn, which became a criminal offence in April, is finally being taken seriously.

Sarah Green, acting director of the End Violence Against Women coalition, said: "These statistics show it is likely that awareness of so-called revenge pornography has grown and that victims likely feel more confident that this crime will be taken seriously if reported.

"We urge the police and courts to continue the pursuit of those who commit this horrible offence.

"And we also urge the Government to step up efforts to prevent this kind of abuse in the first place, by ensuring all young people get good quality sex and relationships education in school where they talk about respect and equality and the law on consent and abuse."

Last year, the Press Association found children as young as 11 had been victims of revenge pornography, with their perpetrators evading justice due to loopholes in the law.

They were among 149 incidents collated by just eight police forces between January 2012 and June 2014. It prompted the CPS to publish new guidelines on how police could deal with revenge pornography offences within existing legislation, before it became law in its own right.

New figures obtained under Freedom of Information (FoI) laws now show 14 forces recorded a total of 139 revenge porn allegations in the six months to April 2015. These included ten victims under the age of consent, while two were aged in their 60s.

There was also a rise in police action - from six people being cautioned or charged from January 2012 to June 2014, to 13 charged during the most recent period, although many said cases had not yet reached a conclusion. Before April, people could be prosecuted under harassment and indecency laws.

A CPS spokesman said: "Revenge porn is a particularly nasty crime and we have been bringing successful cases to court for some years under existing legislation.

"The term was included in CPS legal guidance, as it became apparent this type of offending was growing, in order to make it clear to police and prosecutors which legislation could be used to prosecute.

"The new offence has added to the powers available to prosecutors, and the CPS will use this legislation to bring the strongest possible cases to court."

A total of 14 police forces provided the Press Association with details of revenge porn cases. They were: Cheshire, Dyfed Powys, Essex, Greater Manchester, Hertfordshire, Humberside, Leicestershire, Merseyside, North Yorkshire, Northamptonshire, Northumbria, South Wales, Thames Valley and West Yorkshire. The remaining forces either had no record of any complaints, or refused to provide data due to FoI time limits.

It means the amount of revenge porn cases is likely to be much higher than the figures suggest.

Jef McAllister, managing partner at London-based law firm McAllister Olivarius which represents sex abuse victims, said: "The CPS guidelines, plus the new law banning revenge pornography and the surrounding publicity, have clearly encouraged victims to come forward.

"However, the new law and guidelines are just the tip of the iceberg when it comes to eliminating the problem. Websites that encourage and profit from revenge pornography are not covered by the law, victims usually can't get the material taken down unless they own the copyright and less than 10% of allegations result in a caution or a charge. Criminal prosecutors are already stretched

"We'd like to see a parallel civil law introduced, to permit victims to sue perpetrators for damages and to take out injunctions against them.

"This would increase the ways perpetrators could be pursued, help online images to be removed more quickly and relieve pressure on the police and criminal justice system. Introducing a civil remedy would give victims more options as, in many cases, women do not want to criminalise the men they once loved."

Criminal Justice Minister Mike Penning said: "Revenge porn is an abuse of trust that can leave people feeling humiliated and degraded.

"By making it a specific offence, and running a campaign specifically launched at potential perpetrators, we have sent a clear message that this vile crime will not be tolerated.

"It is vital that victims have the confidence to report cases and know they will be taken seriously and these figures show this is happening."