1. The moral case for the British Empire: an analogy. You are sitting with your family at home one day when a thuggish family with guns and loads of money kicks down your front door and tells you they are going to be squatting in your house for a while.

2. They move in and tell you and your family to squeeze into the spare bedroom because the rest of the house is theirs now. They develop new rules for running the house for which they all vote. Their rules include your family preparing their food and ..

3.... keeping the place tidy. You must look after their youngest kids until they grow old enough to despise you. Your own kids’ fighting annoys them so they tell you that if you don’t sort it, they will. Your family must refer to theirs as sir or madam.

4. If you step out of line they readily use violence against you. They buy a new TV and sofa and they upgrade the wifi but you have to get special permission to use them. Generally, the answer is ‘no’.

5. Same goes for the tutor they bring in for their kids. Finally you’re able to catch them when they’re at their weakest moment dealing with other, even more thuggish families who picked a fight with them down the street. You kick them out and change the locks.

6. But what they did was morally defensible because you got the keep the TV, sofa and wifi and inherit their rules and the method by which they voted for them. You also got some peace from your own kids fighting.

7. Oh, and in some households, such families never actually left. They are now quite settled. Just remember though, the empire brought both good and bad and the good makes it all morally defensible.