Justine joined Humberside Police as Chief Constable on 1 April 2013.
Justine joined Greater Manchester Police (GMP) on the graduate entry scheme in 1988.
She spent three years as a Constable learning the job and was promoted Sergeant serving in Manchester City Centre and Moss Side.
She was promoted to Inspector in 1993 and performed a mixture of roles from operational inspector to staff officer and also a posting to the regional crime squad.
In 1997 Justine became the Chief Inspector for Manchester City Centre leading the sub divisional operational resources to deal with the many challenges of such a high profile post.
In 1999 Justine moved to Merseyside Police as a Superintendent. Whilst there she headed up the Operational Support Unit containing Mounted, Firearms, Roads Policing, Air Support, Dogs and the Support Group and took the silver command role on many high profile football events and the Grand National. Her second posting in Merseyside was as Operations Supt at Toxteth; a challenging inner city role.
In 2003 Justine returned to GMP on promotion to Chief Superintendent, taking up command of the large, complex and demanding North Manchester Division. Whilst there she restructured the Division into a Basic Command Unit and built a strong effective partnership with Manchester City Council. She also commanded many major events such as football internationals during the Wembley rebuild, the Labour Party Conference and Stop The War protests as well as dealing with many high risk operational challenges.
In 2007 Justine became an Assistant Chief Constable (ACC) in GMP taking the territorial policing portfolio overseeing 12 Divisions and a large part of the £560 million budget as well as leading on Citizen Focus, public order, events and football. She later also took command of the regional Northwest Counter Terrorism Unit establishing strong working partnerships with regional forces, national and international agencies.
In 2008, Justine had what was probably the most challenging year of her service. In March, the Chief Constable of GMP, Michael Todd, died suddenly under challenging circumstances. Justine and other command team colleagues worked hard together to ensure the Force and its staff were able to get through this difficult time.
In May, she was Gold Commander for the UEFA Cup Final between Zenit Saint Petersburg of Russia and Rangers FC at the City of Manchester Stadium, where a significant number of fans rioted in the city centre after the game. In June, a firearms officer was fatally shot during a training exercise and Justine led on this critical incident. With all three of these incidents occurring within a ten week period, not only her policing skills but also her resilience were severely tested.
Justine took up the role as Deputy Chief Constable in Tayside Police in February 2009; a Force with 1200 officers, 600 staff, a budget of £70 million, covering an area of 2896 geographically diverse square miles, with a population of around 388,000.
In this role, she introduced a planning and governance framework to enhance service delivery and led on the Best Value Review Programme of operational policing and governance, which have resulted in enhanced planning, reflecting community needs and a new community policing model. She also led a Use of Discretion project and introduced a learning framework around critical incidents which have improved operational practice, assisted officers in making value based decisions and reduced criminal justice proceedings whilst increasing crime reduction performance.
In August 2009, Justine was temporarily promoted to Chief Constable of Tayside Police, a move which was made substantive in February 2010.
During her time as Chief Constable, she achieved unprecedented performance results, most of which exceed the Scottish average whilst also improving on public satisfaction rates.
She transformed the way the service was delivered whilst reducing the budget by 8%. She chaired the People, Development and Diversity Business Area for the Association of Chief Police Officers in Scotland (ACPOS) to deliver a national framework for development and performed the role of Vice President of ACPOS from April 2011 till her departure.