Dame Ursula Brennan DCB (born 28 October 1952) is a retired British civil servant and a former Permanent Secretary at the United Kingdom's Ministry of Justice where she was also the Clerk of the Crown in Chancery.

[1][2] From 2004 to 2006, Brennan served as the director-general of the Living Land and Seas division at the Department for Environment, Food and Rural Affairs (Defra).

[3] Brennan led the review to create a new structure for the Ministry of Justice, where she worked from April to September 2008 as director-general of Corporate Performance.

Her area of responsibility encompassed leadership of the corporate functions in the Ministry, including finance, IT, human resources, strategy and planning, communications, and research and analysis.

She was appointed Permanent Secretary of the Ministry of Defence in October 2010, replacing Sir William Jeffrey.

"[5] She also oversaw the 2011 investigation into the conduct of then Minister of Defence Liam Fox, who had allowed his friend Adam Werritty to join him on foreign missions, attend official diplomatic meetings and, despite having no security clearance, visit him repeatedly at the Ministry office.

[6] On 12 June 2012, it was announced by Sir Bob Kerslake, Head of Civil Service, that Brennan would return to the Ministry of Justice as Permanent Secretary and Clerk of the Crown in Chancery.