According to information on Gov.uk if you are supervising a learner driver on a lesson, then that means that you are legally responsible for the car, therefore could land a fine for committing offences - This means it is illegal for the instructor to touch their phone while sitting in the passenger seat.
Offending drivers could be handed a £200 fine and penalty points while in the passenger seat in certain circumstances.
Neil Greig, IAM RoadSmart Director of Policy and Research, said: "Supervising a learner actually puts you in the driving seat so legally you must treat it in the same way as if you were behind the wheel.
"Learning to drive is stressful enough without a passenger beside you who is more worried about posting than parking."
Mobile phone driving laws were introduced in December 2003 which saw motorists handed a £60 fine for an offence before rising to £100 in 2013.
Fine increased to £100 and penalty points endorsements doubled in 2017, to act as a further deterrent.
Drivers could face a maximum fine of up to £1,000 of a phone driving law offence.
The law still applies to you if you’re stopped at traffic lights and queuing in traffic.
To be able to use a phone while driving it must be mounted to a hands-free device and not touched while on the road.
Hands-free devices include:
- a bluetooth headset
- voice command
- a dashboard holder or mat
- a windscreen mount
- a built-in sat nav
Source: https://www.express.co.uk/life-style/cars/1161051/Phone-driving-laws-passenger-seat-fine-penalty-points-UK