Sevenoke was Mayor of London and, as a friend of Henry V, may have been influenced by the MP for Shropshire and King's pleader, David Holbache, who founded Oswestry in 1407.

According to William Lambarde and Richard Johnson (Nine Worthies of London), Sevenoke was a foundling, whose decision to establish the school and almshouses may have been inspired by his early history.

In 1560, in response to a petition by Ralph Bosville and Sevenoaks parishioners, Elizabeth I issued letters patent incorporating the school, giving it the right to use her name, and changing its governance.

Ralph Bosville was Clerk of the Court of Wards and Liveries, a JP and owner of the Manor of Bradbourne near Sevenoaks, and under the conditions of the letters patent, he and his heirs were to serve on the governing body as long as they lived in Kent.

The school also received a number of bequests during the sixteenth century and during this period was brought to wider attention by William Lambarde's A Perambulation of Kent (1576).

[citation needed] He started this revolution, reducing the number of free places to the townfolk and expanding boarding.

Birkett's revolution was continued by George Heslop who increased the size to a peak of 134 boys, although numbers dropped towards the end of the First World War (during which 350 Old Sennockians enlisted).

"[11] The school was a pioneer in the introduction of 'The New Maths', an approach to teaching the subject which made it less abstract, and more engaging for pupils.

[12] The final period of every Wednesday was set aside for the sixth form to attend lectures, usually with a current affairs theme.

Speakers have included public figures such as trade union leaders Ray Buckton (ASLEF) and Hugh Scanlon (AEU), boxer Henry Cooper, philosopher A. J. Ayer and astronomer Patrick Moore.

[15] In 2012, the independent review of A level and IB results, based on government issued statistics, ranked Sevenoaks School first in the UK, ahead of Westminster (17th), St Paul's (22nd), Harrow (34th), Winchester (73rd) and Eton (80th).

While keeping their respective uniforms and leadership teams, the schools share expertise in areas such as teaching, pastoral care and facilities.

[33] This policy was outlined in full in July 2020 by The Daily Telegraph, which revealed that 'in around 20 cases a year' the school inflated predicted grades 'to facilitate the application' of the student to university.

Mary Curnock Cook commented that it was 'embarrassing for Sevenoaks that deliberately overpredicting students’ grades is in writing in their guidelines'.

UCAS confirmed that it had already sent the school a reminder of its guidelines, and the Department for Education warned that 'Schools should not be inflating predicted grades'.

The school 'refuted any suggestion that we would unfairly exaggerate UCAS predictions' and then announced that it would edit the staff handbook to 'ensure there is no confusion'.