Creator Tom Bidwell described the series as "my dream project and my oldest idea," reimagining Sherlock Holmes as a drug addict and delinquent while the street kids actually solve the cases and he takes the credit.

Netflix announced the project on 20 December 2018, developing it with writer Tom Bidwell based loosely on the Baker Street Irregulars from Arthur Conan Doyle's stories.

Harrison Osterfield's character Leopold, a prince with haemophilia, is based on Queen Victoria's real-life youngest son, Prince Leopold, Duke of Albany.

The series was filmed across the UK, including Dorfold Hall in Nantwich, several locations in Liverpool and the Wirral (such as St George's Plateau, the Sefton Park palm house, Falkner Street, and Birkenhead Park), the Gladstone Pottery Museum in Stoke-on-Trent, Abbey Square in Chester, and locations in North Wales and Ellesmere Port.

Filming was temporarily halted in January 2020 after a cast member was injured on set on Ormond Street in Liverpool.

Production was interrupted and resumed in stages, with some scenes originally planned for March 2020 not being filmed until August 2020.

The series holds an 80% approval rating on Rotten Tomatoes from 40 critic reviews, while Metacritic gave it a more mixed score of 60 out of 100 based on 12 reviews.

Despite topping Nielsen's Original Streaming Shows Charts and beating Disney+'s The Falcon and the Winter Soldier, Netflix cancelled The Irregulars after just one series on 4 May 2021, despite a second season having been scheduled to film in Liverpool that summer.