Lib Peck became the first Director of the Mayor of London's Violence Reduction Unit established in 2019 to adopt a public health approach to reducing violence. The Unit champions prevention and early intervention through investment, policy and research, and drives change by working closely with young people and communities, and in strong partnership with London's 32 councils, the NHS and Met police.

Post pandemic, Lib also co-led London's mission to reach over 100,000 most disadvantaged young Londoners with a mentor.

Prior to that, Lib was the leader of Lambeth Council for seven years and the first female leader for over 20 years. In that role she focused on reducing inequality, improving the borough's physical and creative infrastructure, and initiating its environmental sustainability work. While Leader, Lib was the deputy chair of London Councils leading on crime and community safety, and was the deputy Labour chair of the Local Government Association.

Lib has worked with and for many VCS and community groups.  