Two men are to be charged in the first UK prosecutions under the Female Genital Mutilation Act, the Crown Prosecution Service (CPS) has announced.

Dr Dhanuson Dharmasena and Hasan Mohamed will be charged when they appear before magistrates at Westminister magistrates court next month. The case relates to a medical procedure performed on a patient at the Whittington hospital, in north London, in 2012.

Announcing the decision, Alison Saunders, the director of public prosecutions, said: "The CPS was asked to consider evidence in relation to this allegation of female genital mutilation (FGM) by the Metropolitan Police Service. It was alleged that following a patient giving birth in November 2012, a doctor at the Whittington hospital, in London, repaired FGM that had previously been performed on the patient, allegedly carrying out FGM himself.

"Having carefully considered all the available evidence, I have determined there is sufficient evidence and it would be in the public interest to prosecute Dr Dhanuson Dharmasena for an offence contrary to S1 (1) of the Female Genital Mutilation Act (2003).

"I have also determined that Hasan Mohamed should face one charge of intentionally encouraging an offence of FGM, contrary to section 44(1) of the Serious Crime Act (2007), and a second charge of aiding, abetting, counselling or procuring Dr Dharmasena to commit an offence contrary to S1 (1) of the Female Genital Mutilation Act (2003). These decisions were taken in accordance with the Code for Crown Prosecutors."

The identity of the patient has not been revealed. Dhamasena, 31, from Ilford, Essex, and Hasan Mohamed, 40, from north London, will appear at Westminster magistrates court on 15 April.

The CPS confirmed it had decided to discontinue work on four other allegations, some of which were being reviewed again. The CPS said: "We have determined there is insufficient evidence to demonstrate a realistic prospect of conviction and that no further action should be taken in relation to these four cases." The prosecution service is liaising with the police on two further inquiries.

FGM has been a criminal offence in England and Wales since 1985, when the Prohibition of Female Circumcision Act 1985 was passed. The Female Genital Mutilation Act 2003 repealed and replaced the 1985 act in England, Wales and Northern Ireland.

It also made it an offence for UK nationals or permanent UK residents to carry out FGM abroad, or to aid, abet, counsel or procure the carrying out of FGM abroad, even in countries where the practice is legal. The maximum penalty was also increased from five to 14 years' imprisonment.

Under section 1(1) of the Female Genital Mutilation Act (2003) a person is guilty of an offence if he excises, infibulates or otherwise mutilates the whole or any part of a girl or woman's labia majora, labia minora or clitoris.

Efua Dorkenoo, from Equality Now, who has been campaigning to end FGM, said: "Getting a prosecution after so long is fantastic and a key part of ending FGM. A prosecution will send out a strong message that FGM will not be tolerated. However, we also need to ensure that girls at risk are urgently protected; survivors need to be empowered and given the physical, psychological and emotional support they need to speak out.

"Eliminating FGM means having a 'joined-up' approach where everyone is working together. Front line professionals and others in regular contact with children need to know what their roles and responsibilities are in relation to reporting and safeguarding. The campaign is moving so quickly now we cannot afford to lose momentum. We need to ensure that every single girl is protected."

John Cameron, the NSPCC's head of child protection operations, said: "This is great news for the fight against FGM. The fact that we hadn't previously had a prosecution in the UK for this child abuse despite it being a crime for almost 30 years is unacceptable.

"Today's announcement by the Crown Prosecution Service sends out a strong message that they are taking FGM seriously. FGM is a public health issue that needs increased collaboration from professionals across health, education and the police."

Commander Mak Chishty, the lead officer for the Association of Chief Police Officers on FGM, said: "Across the country, police are working extensively to investigate and build strong cases against those suspected of inflicting or aiding or abetting female genital mutilation.

"Female genital mutilation is a barbaric crime that has no place in modern day Britain. The police are committed to working closely with health services, schools, colleges, social services and third sector organisations which have an understanding of this form of abuse and can help us reach those who may be at risk.

"Prosecutions of those who continue this horrific and outdated practice should signal a warning to those who've committed or are considering inflicting female genital mutilation as well as anyone who assists them or stays quiet when they know this abuse has been committed; we are pursuing offenders and working to bring them to justice so that we can protect victims – some of them painfully young – and stamp out this appalling crime."