Guidance from the RoSPA safety charity, Driving for work: mobile phones, strongly discourages the use of hands-free mobiles when driving, indicating that “a substantial body of research shows that using a hand-held or hands-free mobile phone while driving is a significant distraction and substantially increases the risk of the driver crashing”. Mobile phone users are four times as likely to crash, injuring or killing themselves or other people. The guidance is available from its website.