David Peter Williams CB (born December 1968[2]) is a British civil servant who has served as the permanent under-secretary of state for defence since April 2021, succeeding Stephen Lovegrove.

[3] He served as the second permanent secretary at the Department of Health and Social Care since the beginning of the COVID-19 outbreak in the United Kingdom in March 2020.

[3] Prior to his current role, Williams served in various other administrative positions in both the Department of Health and Social Care and Ministry of Defence since 2015.

He is a policy leaders fellow at the University of Cambridge's Centre for Science and Policy.

[4] He was appointed Companion of the Order of the Bath (CB) in the 2020 New Year Honours "for services to Government Finances.