National manager of road policing, Superintendent Steve Greally, said anything that took a person's attention away from the road was a safety risk.
"If someone is concentrating on an email, they are not likely to be giving their full attention to driving."
Road safety group Brake's director Caroline Perry also said the content of the email could be a distraction regardless of whether the driver interacted with the device. "If a distressing email comes through that can elevate stress levels at the wheel."
The Automobile Association's motoring spokesman Dylan Thomsen was pleased the app's developers were trying to use technology to make mobile devices less distracting but the best option was still for people to pull over if they needed to use their phones.
"Tools like this are looking at reducing physical distractions, but you're taking away some of your mental focus. "
Go to the app store or www.speaking.email