Jeremy John Heywood, Baron Heywood of Whitehall, GCB, CVO (31 December 1961 – 4 November 2018) was a British civil servant who served as Cabinet Secretary to David Cameron and Theresa May from 2012 to 2018 and Head of the Home Civil Service from 2014 to 2018. He served as the Principal Private Secretary to Prime Ministers Tony Blair and Gordon Brown from 1999 to 2003 and 2008 to 2010. He also served as Downing Street Chief of Staff and the first Downing Street Permanent Secretary. After he was diagnosed with lung cancer, he took a leave of absence from June 2018, and retired on health grounds on 24 October 2018, receiving a life peerage; he died 11 days later on 4 November 2018.

Heywood was born on 31 December 1961 in Glossop, Derbyshire, England. His parents were Peter Heywood and Brenda Swinbank, who met as teachers at Ackworth School in West Yorkshire, one of a few Quaker educational establishments in England.

Heywood was educated at the private Quaker Bootham School in York, where his father taught English. He studied history and economics at Hertford College, Oxford (where he was later made an Honorary Fellow), graduating with a Bachelor of Arts (BA) degree in 1983. He later studied economics at London School of Economics and received his Master of Science in 1986. He also attended the Program for Management Development at Harvard Business School in 1994.

From 1983 to 1984, Heywood worked as an economist at the Health and Safety Executive, before moving to the Treasury, and became the Principal Private Secretary to the Chancellor of the Exchequer, then Norman Lamont, at the age of 30, having to help mitigate the fallout from Black Wednesday after less than a month in the job. He remained in this role throughout the 1990s under Chancellors Kenneth Clarke and Gordon Brown. He was economic and domestic policy secretary to Tony Blair from 1997 to 1998, before being promoted to be the Principal Private Secretary to Prime Minister Tony Blair in 1999. He stayed in this position until 2003.

He became a managing director of the UK Investment Banking Division at Morgan Stanley where he was embroiled in the aftermath of the collapse of Southern Cross Healthcare.

Upon Gordon Brown becoming Prime Minister in 2007, Heywood returned to government as Head of Domestic Policy and Strategy at the Cabinet Office. In January 2008 he was once again appointed Principal Private Secretary to the Prime Minister; (it has sometimes been claimed that he was subsequently and additionally appointed to the position of Downing Street Chief of Staff, after Stephen Carter's resignation as the Prime Minister's Chief of Strategy, but Heywood himself denied that this was ever the case).

In 2010, after David Cameron became Prime Minister, Heywood was replaced as Principal Private Secretary by James Bowler. He returned to the civil service and was subsequently appointed the first Downing Street Permanent Secretary, a role created for the purpose of liaising between the Cabinet Secretary and the Chief of Staff within the Cabinet Office.

On 11 October 2011 it was announced that Heywood would replace Sir Gus O'Donnell as the Cabinet Secretary, the highest-ranked official in Her Majesty's Civil Service, upon the latter's retirement in January 2012. It was also announced that Heywood would not concurrently hold the roles of Head of the Home Civil Service and Permanent Secretary for the Cabinet Office, as would usually be the case. These positions instead went to Sir Bob Kerslake and Ian Watmore respectively. On 1 January, Heywood was knighted and officially made Cabinet Secretary. In July 2014 it was announced that Kerslake would step down and Heywood would take the title of Head of the Home Civil Service in the coming Autumn. In September, Heywood duly succeeded Kerslake. As of September 2015^[update], Heywood was paid a salary of between £195,000 and £199,999, making him one of the 328 most highly paid people in the British public sector at that time.