Former top civil servant Simon Case has taken his seat in the House of Lords.
The 46-year-old, who served four prime ministers, joins the independent crossbenches in the unelected chamber, which scrutinises legislation and acts as a check on the Government.
Lord Case wore the traditional scarlet robes for the short introduction ceremony in the chamber, where he swore allegiance to the King.
He was supported by former Whitehall chief Lord Butler of Brockwell and Lord Chartres, a retired bishop of London.
Lord Case became cabinet secretary and head of the Civil Service aged just 41 in September 2020, having previously served as private secretary to the Duke of Cambridge.
He had also worked for the GCHQ intelligence agency.
He stepped down from the top Whitehall job at the end of 2024 on health grounds after a turbulent four years in the role, which included the Covid-19 pandemic, Tory infighting, the Russian invasion of Ukraine and the death of Queen Elizabeth II.
His tenure was not without controversy, as he was forced to recuse himself from leading an investigation into the “Partygate” scandal following allegations his office had held a Christmas event during lockdown.
Lord Case was not one of those fined over the episode.
Appointed by Boris Johnson, he held the post under the subsequent administrations of Liz Truss, Rishi Sunak and Sir Keir Starmer.
He was succeeded by Sir Chris Wormald.
