Vodafone UK is offering customers a Family plan for free calling between four to six mobiles for £5 a month.

On person in a group pays the £5 a month, and all calls to three other nominated Vodafone customers are then free within the group. Vodafone caps the call time at 60 minutes, after which customers are charged at their normal rate.

Vodafone has designed the plan to give parents peace of mind that they can get in touch with their children, even if they’ve run out of credit.

The second option is for a group of six people, for which one person pays £7 a month.

The Family plan is available to both prepay and contract customers. There is some small print that says contract customers signing up or recommitting on or after 1 November can only sign up to the plan with an 18 month contract; and the plan excludes roaming calls, video calls, and texts.