Police are investigating increasing numbers of cases where children are being assaulted because of suspicions about witchcraft.

This year so far, 27 cases of ritual child abuse have or are still being investigated by the Metropolitan Police, including two allegations of rape. This compares to to 24 in 2013, 19 in 2012 and nine in 2011. There have ben 148 referrals to the Met since 2004.

Teachers and other professionals who work with children have been invited to meet police at City Hall in London to discuss the problem. 

Allegations included a child being swung around and smacked on the head to "drive out the devil" and youngsters being dunked in water, according to an investigation by the BBC.

Deaths linked to ritual child abuse include Kristy Bamu, 15, tortured and drowned by his sister and her boyfriend in 2010 and Victoria Climbie in 2000, whose aunt and boyfriend had believed she was possessed and who were found guilty of murder.

Det Supt Terry Sharpe said ritualistic abuse was a hidden crime.

"Abuse linked to belief is a horrific crime which is condemned by people of all cultures, communities and faiths. A number of high-profile investigations brought the issue of ritual abuse and witchcraft into the headlines, but it is important that professionals are clear about the signs to look for."

Some families genuinely believed the victim had been taken over by the devil or an evil spirit, he said.

"Regardless of the beliefs of the abusers, child abuse is child abuse."

The independent investigator Richard Hoskings told BBC London 94.9 that most of the cases involved communities from Asia, west and central Africa and that children are being used as scapegots. "Children are being accused of witchcraft and they're being accused of being the source of all the evil that's taking place."

Simon Bass from the Churches' Child Protection Advisory Service said: "We are not remotely surprised that the Metropolitan Police alone has already received 27 referrals of this type this year - or three a month. We are pleased that the Metropolitan Police has undertaken such great work in this area, but we are convinced that this form of abuse is hidden, and that the statutory agencies across the UK are facing similar situations."