"The penalty for this is the same as drink driving. "
If only, Eddie, if only (though in my view it should be).
The maximum penalty for drink-driving is 6 months in prison. The offence carries a mandatory 12 month disqualification (36 months for a second or subsequent offence committed within 10 years of the first). The disqualification period is increased as the detected alcohol reading gets higher. The maximum penalty for using a hand held phone is a fine of £1,000 (£2,500 if driving an HGV or a bus). Magistrates have the option to impose a discretionary disqualification but the usual disposal is three penalty points. Most offences are dealt with by a fixed penalty of £100 and three points.
From the government's website on the mobile phone matter:
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When you can use a phone in your vehicle
If you’re the driver, you can only use your phone in a vehicle if you:
need to call 999 or 112 in an emergency and it’s unsafe or impractical to stop
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Quite whether the circumstances described by MantRay necessitate calling 999 as an emergency is debateable and if a prosecution followed the courts would have to decide the matter.