A widespread rumour regarding child exorcism is now spreading among African communities and churches in London. Evangelicals warn that some cases are alleged physical abuse, mental abuse or even emotional abuse. The Metropolitan Police is currently investigating a number of cases of so-called "faith crimes".

According to preliminary investigation, abuses are taking place in places of worship, particularly within the African churches. Children accused of being possessed by evil spirits have been forced to submit to terrifying exorcism ceremonies in which they suffered from beatings to genital mutilation. Others have suffered emotional abuse after being traumatised during the ceremonies.

BBC Newsnight's study found that the problem is often being understated by local authorities. A third of all London boroughs did no work at all on the issue of the effects of child exorcisms, including Lambeth in south-east London which has the biggest African population in the UK.

Katei Kirby of the African Caribbean Evangelical Alliance (ACEA) said it was important to keep the issues in context.

"Exorcism is a good thing but it's not meant to be abusive, there's no biblical precedent for that," she said.

"It's important social services work with the faith communities to understand them and make sure they're not misinterpreting the culture but challenging anything that's immoral or unsafe for children."

Superintendent Chris Bourlet, of Child Abuse Investigation Command, is now investigating some cases of abuse in churches. Experts say exorcism is generally related to the belief culture of African countries like the Congo and Angola.

"We’re not interested in attacking culture belief systems, we just want to protect children," he added.

A Christian charity, Churches' Child Protection Advisory Service (CCPAS) said it was vital cultural considerations did not take precedent over a child's welfare. David Pearson of CCPAS said, "Abuse is abuse, and can never be overlooked or mitigated against by cultural or religious factors."

Africans Against Child Abuse (Afruca) spoke out with concern that church leaders who believe in possession needed education on child protection.

"It's part and parcel of what churches do in terms of freeing people from what they see as the stranglehold of the devil. But it does worry me that local authorities are not making the effort to link up with the churches in terms of their practices regarding child protection," spokeswoman Debbie Ariyo said.