Philippa was born in 1674 or 1675, the fourth of five daughters and the coheir of John Bourchier, a doctor from Ipswich.
She married William Walton, a London merchant who in 1702 took over the powder mills at Waltham Abbey.
[3] With a rising demand for gunpowder thanks to the outbreak of the War of the Spanish Succession (1701–1714) William was awarded his first contract in 1702, soon after acquiring the mills.
[3] Following his early death in 1711, Philippa, at that time 36 years old and with ten young children, took over the enterprise.
[3] Meanwhile, in the wake of the outbreak of the Seven Years' War, the Waltham Abbey gunpowder factory was becoming an increasingly important asset for the British Army.