What is a Green card and why would you need one?

In the event of a no deal Brexit motorists travelling between Britain and Ireland will need a Green Card but what is and how do you get it? Geraldine Herbert explains   What is a green card? Currently, when you take your car to any country within the EU including the UK you are covered by the terms of the EU Motor Insurance Directive (MID).  Essentially what this says is that anyone who holds a  motor insurance policy in an EU...