I should immediately say that according to most of the information available on the internet and from reputable car hire companies, an IDP is not required for UK drivers in the EU.
However...
I recently visited Italy (Sardinia) and hired from a company that were cheap, and apparently scammers, as they claimed it was now necessary to have an IDP in Italy according to a recently passed Italian Codice, and refused to let the car out unless I bought their full insurance. My options were to walk out and pay a similar amount for a last minute car somewhere else, pay the money, or get the train and do without (not really an option).
The company in question was SurPrice via Expedia, and had I checked on TripAdvisor, the situation would have been obvious
So you can draw your own conclusions very easily. It may be worth getting an IDP anyway for the small cost and effort involved - and in case it actually does become an issue more widely. I would like to blame Brexit, but I'm pretty sure it was a straightforward Brexit-enabled scam.
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