Heath, son of carpenter/builder, Scholarship to Oxford
Wilson, father was an industrial chemist, scholarship to go to school, bursary to go to university
Callaghan, father enlisted man in the Navy, then the coastgard, and died young leaving family relying on charity. Got a place at uni but couldn't afford to go
Thatcher, father was a grocer. Got to Oxford on a scholarship, studied Chemistry
Major, Parents were in theatre, then ran a garden shop, lived in a rented flat, left school at 16, did a banking correspondence course while failing to get a job as a bus conductor
Blair, Father was a university lecturer, went to boarding school at Fettes, took a gap year then did Law at Oxford
Blair brought in the posh = good, Champagne Socialists era. It's also what powered Labour - the alliance of the metropolitan left and the working class left (the latter having gone to the tories now)
Brown and May had normal backgrounds, but Blair, Cameron and Johnson are very different to Heath, Wilson, Callaghan, Thatcher, Major, Brown and May.