The "Ignore No More" app was invented by Sharon Standifird for all parents who have gone through the experience of trying in vain to reach their children.

Furious after she wasted an entire day attempting to contact her son Bradley by phone call and text, Mrs Standifird said the idea for the app came to her as soon as she knew he was safe.

Mrs Standifird decided that what was needed was an app that "just shuts their phone completely down and they can't even use it".

"I literally just started researching how to develop an app," she added.

The app took several months to create and is now available for Android phones via Google Play at a cost of $1.99.

Mrs Standifird, a former soldier from Houston, Texas, who served in the Gulf, is working on developing a version of the app for the iPhone.

Once disabled, the child's phone can only make calls to a list of pre-selected numbers, and they must contact one of the people on the list to obtain a code to reactivate it.

In the process, they are forced to check-in with their parent or another carer on the list.

The phone can still be used to dial emergency numbers.

Mrs Standifird said: "Bradley needs to call me because I'm the person that has the unlock password."

She told ABC News: "It takes away texting, it takes away the gaming, it takes away calling their friends. I do have to say that he responds to my texts and my calls a whole lot quicker than he used to."

However, the elusive Bradley was less convinced of the phone's necessity.

He told ABC: "I thought it was a good idea, but for other people, not me."

The Telegraph, London