Some countries which you may choose to visit and hire a car require an International Driving Permit (IDP). This is a document which allows the permit-holder to drive a private motor vehicle in that country. To be valid the IDP must be accompanied by a valid licence from the home country. The IDP is essentially a multiple language translation of the permit-holder's normal driver's licence, complete with photograph and vital statistics. It is not, however, a licence to operate a motor vehicle on its own.
If the UK leaves the EU without a deal, you might need an IDP to drive in the EU and European Economic Area (EEA).
A list of countries requiring IDPs can be found here - https://www.gov.uk/driving-abroad/international-driving-permit
IOM Residents can download a form here https://www.iompost.com/for-you/other-services/vehicle-amp-driving-licences/
UK Residents can obtain IDPs from...
If you are a visitor, resident or student in Great Britain (GB) and still have a driving licence issued in the country you have come from, there are certain conditions that affect how long you can drive, and what you can drive in Great Britain – see www.direct.gov.uk/en/motoring/driverlicensing/drivingingbonaforeignlicence/dg_4022561