Police and intelligence agencies should make greater use of child spies to investigate terrorists, gang violence, drug dealing and sexual exploitation, says the UK’s security minister despite legal concerns over their safety.

Ben Wallace says there is “increasing scope” to recruit “juvenile”undercover agents because of the growing numbers of children involved in serious crime both as perpetrators and victims.

Records show the children - most aged 17 - have already been used as “covert human intelligence sources” (CHIS) by police in the past three years to provide information on murder, gang violence, drug dealing and the use of weapons.

The evidence emerged in a legal challenge in the High Court by campaign group Just for Kids Law who maintain there are a lack of safeguards to protect the children from potential physical and emotional harm. They claim the failings are a breach of the children's human rights.

The Home Office is defending the action, maintaining that they are only used when necessary and that they can play an important part in tackling serious crime.

In documents before the court, Mr Wallace said it was important to recognise young people could have “unique access to information that is important in preventing and prosecuting gang violence and terrorism.”