Hassell says he discovered the attack while working on a more benign app of his own: one that would create a child safety setting for Android phones.

FORBES: Researchers Show Android Vulnerable To App-Hijacking Attacks

The governor praised Mr Clements' track record, saying he had found ways of improving prison safety and setting up programmes that helped offenders reintegrate successfully after leaving prison.

BBC: Colorado prisons chief Tom Clements shot dead

They have set up the National Patient Safety Agency, which is setting up a national register of such events so that national lessons can be drawn from local mistakes.

BBC: Keeping patients safe