Police are urging parents to check the group WhatsApp settings on their children's phones after a number of 11 year olds in Gloucestershire were exposed to sexual violence and racist content.

Officers have received reports that children in the county have been automatically added to a group without their knowledge or permission.

Once in the group, which has an American phone number prefix, they are encouraged to add everyone in their contacts and are then sent upsetting sexually violent and racist content.

Group members are then warned that if they leave the chat, they will be found.

Police are now asking parents whose children use WhatsApp to check the settings on the messaging app so that they cannot be added to groups by unknown third parties.

The default setting in WhatsApp allows anyone to add a number to a group chat without needing permission.

To disable this, go to WhatsApp and follow these steps:

• Go to Settings
• > Privacy
• > Groups
• > Under 'who can add me to groups', select ‘My contacts’

Parents are also advised to talk to their children and advise them not to view the chat if they have been added to the group and to block, delete and report the group to WhatsApp immediately.