Sir Peter Kenneth Estlin KStJ (born July 1961) was the 691st Lord Mayor of the City of London and is a British businessman.

He was chief financial officer for Salomon Brothers Asia, and then for Citi's Investment and Corporate Banking divisions in New York and London.

He joined Barclays bank in 2008 and was appointed Acting Group Chief financial officer in August 2013.

[4] His mayoral theme was Shaping Tomorrow's City Today, promoting the sheer scale of innovation taking place in the UK, alongside championing digital skills, particularly to create a more inclusive society.

Sir Peter was appointed Knight of the Order of Saint John[5] and an honorary bencher of Middle Temple in 2018.