He is currently Deputy Chief Constable of the Police Service of Northern Ireland since November 2024.

[1][2] Singleton was one of the first recruits of the Police Service of Northern Ireland in 2001 and has held a number of positions since joining.

[3] In 2014, he was promoted and became responsible for the delivery of community policing across Belfast, then in 2016, he became head of the newly established Paramilitary Crime Task Force as a Detective Superintendent.

[4] In 2019, he was promoted to Detective Chief Superintendent and became head of the Legacy Investigation Branch.

In 2021, the Northern Ireland Policing Board announced that Singleton had been appointed a temporary Assistant Chief Constable, becoming head of the Community Safety Department.