It’s a good question. The last genuine PM we had was John Major, the son of a gardener who studied at night school while working for his father during the day. Before him was Maggie Thatcher, an industrial chemist by trade.
All since then have been career politicians from the political class. Blair went to Fettes, the “Scottish Eton”. Cameron and Boris were classmates at Eton and Oxford. Even Jeremy Corbyn, supposed champion of the Workers never worked a day in his life. He will likely be followed as leader of the Labour Party by Sir Kier or Lady Nugee.