In 1961, shortly after getting a job as a lecturer at Cambridge, my father had an idea. The faculty buildings, he discovered, were largely unused for six months of the year. The colleges, too, were empty. Why not create two Cambridges, one for term time and one for the holidays? Unlike the Cambridge of dreaming spires and glittering prizes, the second would be for ordinary people who’d missed out on the chance of a university education — labourers, tradesmen, clerks, housewives.