The DLVA have recently abolished the Counterpart driving licences, so if you are soon to be hiring a car for a trip abroad or once you are on holiday, then in advance of the hiring, you need to access the Share Driving License website and enter your license number, the postcode to which the licence is registered and your National Insurance number. This will then produce a reference code for you to give to the Car Hire firm, so that they may check you records to see if you are acceptable to them for the vehicle you hire; such as your class of licence or that you don't have too many penalty points.
However the online reference number given only lasts for 72 hours after which you need to log on again and get another reference if you have not already hired a vehicle.
So if you go aboard take a note of your Drivers Licence number and National Insurance number (hopefully you remember your postcode!), so you can be prepared for that Icelandic Volcano eruption, which might permit you to hire a car in Spain and drive to Calais, to get home rather than wait for the airline to start flying again!
As the new system may take a while to be implemented I suggest you still bring your drivers licence with you just to be sure.
https://www.gov.uk/view-driving-licence
https://www.gov.uk/government/publications/how-to-share-your-driving-licence-information
www.gov.uk/view-driving-licence