Robert Hanbury Brown was born on 31 August 1916 in Aruvankadu, Nilgiri Hills, South India; he was the son of an Officer in the Indian Army, Col. Basil Hanbury Brown, and of Joyce Blaker. From the age of 3 years Hanbury was educated in England, initially at a School in Bexhill and then from the ages of 8 to 14 years at the Cottesmore Preparatory School in Hove, Sussex. In 1930 he entered Tonbridge School as a Judde scholar in classics. Hanbury's interests turned to science and technology, particularly electrical engineering, and after two years he decided that he would seek more appropriate education in a technical college. His decision was accelerated by the fact that after the divorce of his parents his mother had married Jack Lloyd, a wealthy stockbroker, who in 1932 vanished with all his money and thus Hanbury felt he should seek a career that would lead to his financial independence. For these reasons Hanbury decided to take an engineering course at Brighton Technical College studying for an external degree in the University of London. At the age of 19 he graduated with a first-class honours BSc, taking advanced electrical engineering and telegraphy and telephony. He then obtained a grant from East Sussex and in 1935 joined the postgraduate department at the City & Guilds, Imperial College. In 1936 he obtained the Diploma of Imperial College (DIC) for a thesis on oscillators
He intended to continue his course for a PhD but a major turning point in his career occurred when he was interviewed during his first postgraduate year by Sir Henry Tizard FRS, Rector of Imperial College. Hanbury explained to Tizard that he was following up some original work by Van der Pol on oscillator circuits without inductance and hoped, ultimately, to combine an interest in radio with flying. In fact, Tizard had already challenged him about the amount of time he spent flying with the University of London Air Squadron.
Tizard told Hanbury to see him again in a year's time and that he might then have a job for him. In fact, within three months Tizard accosted Hanbury and said he had an interesting research project in the Air Ministry for him. After an interview by R.A. (later Sir Robert) Watson-Watt (FRS 1941), Hanbury was offered a post at the Radio Research Board in Slough. His visit to Slough was brief; he was soon told to report to Bawdsey Manor in Suffolk, which he did on 15 August 1936. Thereby, unaware of what Tizard had in mind for him, Hanbury's career as one of the pioneers of radar began.