Ms Pierson, 53, has been chief of staff at the agency. The Secret Service last year became embroiled in a scandal involving employees taking prostitutes to their hotel rooms in Colombia ahead of Obama’s visit to that country.

The service’s director for most of the past seven years, Mark Sullivan, apologised for the scandal and announced his resignation last month.

A veteran of the agency, which she joined directly from university and for which she has worked for the past 29 years, Ms Pierson will be in charge of a budget of more than $15 billion and will be responsible for the protection not just of Mr Obama and his vice president, Joe Biden, but of all previous US presidents and their spouses still living, as well as any visiting foreign heads of state and other leaders.

It was founded in 1865 when its main task was to tackle counterfeiting of the currency, at a time when one third of notes and coins in circulation were thought to be bogus. It is now also responsible for safeguarding the US financial infrastructure and payment systems.

Last year Ms Pierson told the Washington Post that she saw her then role as chief of staff as providing “unique opportunities to witness history, while serving as a critical team member protecting our nation’s leaders and financial infrastructure”.

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