It all started with the UK riding on the left of the road, and Europe on the right.
Therefore, as has been said, to turn across oncoming traffic it’s much safer to have the rear brake useable.
Therefore, British Standard is right hand front. Europe standard is the reverse.
In theory, and often in practice, imported complete bikes have to have the cabling reversed by the retailer. It’s even more frustrating when the customer wants it changed back again, in theory only after the “ legal” bike has been purchased. I know a shop that directly imports large numbers of Scotts, and has to reverse the cabling on each one.
When I was young, most UK riders used right hand front. However, more pictures of Merckx, Coppi etc using the reverse made it the trend to use right hand rear.
Nowadays, most serious racers use continental cabling, but even some Belgian and other Continentals use the UK style.
So...... you pays your money and.......