WILLIAM WORDSWORTH FAMOUSLY described the child as “father of the man,” wishing for his days “to be / Bound each to each by natural piety.” Childhood, with a generous portion of filial piety, set the course for Robert Banks Jenkinson's life and career. Early loss of his mother, the world of his Jenkinson relations, and his father's political connections bent the twig from an early age. His family history highlights aspects of British politics and culture that influenced the future prime minister, along with particular differences that set him apart from contemporaries and colleagues. The Jenkinsons sprang from the provincial gentry that had governed England for a century or more. Charles Jenkinson took a common path for ambitious gentlemen without an estate to inherit by pursuing an administrative career that led him into parliament, while his wife's family used a fortune made in India along with ties forged there as a bridge into English society. Young Robert was raised to enter public life. Connections gave him an advantageous start.

Amelia Jenkinson gave birth to her only child at Hawkesbury in Gloucestershire on June 7, 1770, roughly sixteen months after marrying the rising politician Charles Jenkinson. Childbirth proved too much for the nineteen-year-old mother who died within a few weeks of her son's christening at St. Margaret's Westminster in London on June 29. Shattered by Amelia's death, Charles Jenkinson sought advice from the noted physician Anthony Addington, who also attended the Pitt family and occasionally served as Lord Chatham's spokesman in society, before spending three months in solitude to recover. His mother Amarantha Jenkinson took the baby into her care promising that “should God spare my life the loss of a mother I will endeavor to supply to the best of my power.” She hoped that “time, religion, and good sense” would carry Jenkinson through his loss. The pathos of an infant left without his mother struck a resonant chord in the age of sensibility, but it also underlined the predicament father and son faced. The forty-two-year-old widower devoted himself entirely to his son's upbringing and his own official career. Those two sides of his life fit closely together as the ambitious Jenkinson invested future hopes in his son.