Also depends on class middle and upper class breakfast,Lunch and dinner with late night meal being supper.
Working class breakfast, dinner and tea and maybe supper.
People used to eat at different times depending on their status and where they live.
"
.Nearly everyone agrees that breakfast is the first meal of the day. The confusion sets in after elevenses or mid-morning coffee and biscuits.
If you are a member of the lower classes or live outside London and the south-east, the midday meal is called dinner and is often the main meal of the day. But for the upper classes and metropolitans, the midday meal is called lunch and is usually quite light unless taken in a restaurant with friends or business associates.
In the evening, the lower classes and northerners come home from work, school or shopping and sit down to another fairly substantial meal called tea at about 6pm. However, the upper classes and southerners eat later and the meal they eat, called dinner, tends to be the main meal of the day.
For all classes and regions, supper usually means a late-night snack or meal, but some people use the term for the early evening meal if they have already had their dinner at midday. Afternoon tea – a pot of tea with sandwiches and cake once enjoyed by upper-class ladies of leisure – has largely died out but lives on in the form of the 4pm tea and biscuits that people of all classes enjoy."
The link below explains it all.
you may need to subscribe to read that one did not realise till I went back to it can't find any thing else as definitive at the moment..
https://www.ft.com/content/cddae7d0-552b-11db-acba-0000779e2340
The Independent has an article showing the result of a government survey on this matter.
https://www.independent.co.uk/life-...rits-debate-evening-meal-yougov-a8363331.html